330
Speeialia
s u b c o r t i c a I s t r u c t u r e s were affected significantly. Thus, t h e gross b e h a v i o r a l a l t e r a t i o n s were p r e c e d e d b y c h a n g e s in regional perfusion, w h i c h b e c a m e less v a r i a b l e a n d m o r e p r o n o u n c e d w i t h time. B l o o d gases were u n a f f e c t e d a t 10 m i n a f t e r i n j e c t i o n of L S D a l t h o u g h a slight h y p o x i a was o b s e r v e d b y 20 rain. L S D derivatives - Table I I. T h e 2 - m e t h y l - L S D , 6 - n o r - L S D a n d As,9-LSD d e r i v a t i v e s failed to a l t e r r a t b e h a v i o r in a n y o b s e r v a b l e w a y a t a dose level w h i c h was m a r k e d l y effective in t h e case of L S D ; in a d d i t i o n a l s u b g r o u p s of a n i m a l s b e h a v i o r a l effects were n o t d e t e c t e d b e y o n d 40 m i n a f t e r i.v. injection. F u r t h e r m o r e , t h e 2m e t h y l a n d A s,9 d e r i v a t i v e s also failed to a l t e r b l o o d p r e s s u r e or cardiac o u t p u t s . T h e 6-nor-LSD, h o w e v e r , a p p e a r e d m o r e p o t e n t in m i m i c k i n g t h e p e r i p h e r a l effects of L S D b y e l e v a t i n g a r t e r i a l pressures b y a b o u t 40 m m H g a b o v e m e a n pressures a n d s i g n i f i c a n t l y r e d u c i n g c a r d i a c o u t p u t s b y 25~o. N o n e of t h e s e c o m p o u n d s affected regional p e r f u s i o n of t h e b r a i n , w i t h t h e possible e x c e p t i o n of 2 - m e t h y l L S D w h i c h caused a fall in olf a c t o r y b u l b flow. Discussion. T h e flo%v c h a n g e s t o t h e p a r i e t a l a n d f r o n t a l cortex, cerebellar and, p e r h a p s , t h e dorsal h i p p o c a m p a l regions a p p e a r t o b e r e l a t e d to t h e b e h a v i o r a l effects. T h e f i n d i n g s w i t h 2 - m e t h y l L S D , 6-nor L S D , a n d A s, 9 L S D to w h i c h r a t s are n o t v i s i b l y responsive, r e v e a l no c h a n g e s in r e g i o n a l p e r f u s i o n of t h e brain, a l t h o u g h some of t h e s e compounds have considerable peripheral cardiovascular effects (Table II). A s s u m i n g as o t h e r do 8-s t h e n , t h a t regional b l o o d flow in t h e b r a i n is s e c o n d a r y to f u n c t i o n , t h e m o s t p a r s i m o n i o u s e x p l a n a t i o n for t h e s e f i n d i n g s is t h a t t h e flow c h a n g e s signal n e t increases in t h e a c t i v i t i e s of t h e p a r i e t a l , frontal, a n d cerebellar coreices of t h e r a t a t t h e s a m e t i m e t h a t some f u n c t i o n s of t h e dorsal h i p p o c a m p u s p e r h a p s decrease. I n p a s t studies in conscious men~~ a n d a n e s t h e t i z e d cats ~ gross c e r e b r a l perfusion appeared unchanged by LSD administration. T h a t L S D , indeed, increased t h e flow of b l o o d to c e r t a i n areas of t h e b r a i n s of conscious r a t s e m p h a s i z e s o u r c o n t e n t i o n t h a t t h e s e r e l a t i v e l y r e s t r i c t e d r e s p o n s e s were t h e r e s u l t of tissue a c t i v i t y responses likely to b e o b s c u r e d b y whole b r a i n m e a s u r e m e n t s or t h e use of a n e s t h e t i c s 9 A l t h o u g h t h e c h a n g e s in regional p e r f u s i o n of t h e b r a i n m a y signal c h a n g e s in function, t h e p r i m a r y sites of a c t i o n of L S D r e m a i n obscure. Some regions w h i c h r e t a i n r a d i o l a b e l l e d L S D h a v e b e e n i n t e r p r e t e d as possible sites
EXPERIE NTIA31/3
of a c t i o n ~. T h u s , a c c u m u l a t i o n s of L S D i n t h o s e m e s e n cephalic a n d d i e n c e p h a l i c s t r u c t u r e s a s s o c i a t e d w i t h a u t o n o m i c c e n t e r s in t h e b r a i n c o r r e l a t e well w i t h t h e c e n t r a l l y m e d i a t e d a u t o n o m i c effects of t h e d r u g ~. A l t h o u g h L S D also b i n d s s e l e c t i v e l y to a m i n o r i t y of cells in f r o n t a l c o r t e x a n d c e r e b e l l u m t, 2, regions t o w h i c h t h e flow of b l o o d also is increased, t h e w i d e s p r e a d u p t a k e s of L S D in m a n y s u b c o r t i c a l areas are n o t p a r a l l e l e d b y flow changes. A l o n g w i t h ~he a c k n o w l e d g e d effects in subcortical regions t h e n , t h e flow d a t a suggest t h a t some cortical regions a n d c e r e b e l l u m also are r e s p o n s i v e to L S D . A t t h i s time, h o w e v e r , it is inlpossible to d i s t i n g u i s h b e t w e e n s e c o n d a r y f u n c t i o n a l a s p e c t s a n d p r i m a r y sites of d r u g a c t i o n ~3.
Zusammen/assung. Die i.v. V e r a b r e i c h u n g y o n L S D a n R a t t e n s t e i g e r t d e n B l u t k r e i s l a u f i m H i r n s t a m m sowie i m f r o n t a l e n u n d p a r i e t a l e n C o r t e x selektiv. E s w u r d e n d u r c h 6 - N o r - L S D , 2 - M e t h y l - L S D u n d Ao,9-LSD w e d e r w a h r n e h m b a r e V e r h a l t e n s ~ n d e r u n g e n n o c h A n d e r u n g e n des regionalen Blutkreislaufs verursacht. H. GOLDMAN 14, ]~. FISCHER 15, N. NICOLOV 16 a n d S. MURPHY 14
Department o~ Pharmacology, Wayne State University School of Medicine, 5dO East Can/ield A venue, Detroit (Michigan 48201, U S A ) , 9 September 7974.
10 L. SOKOLOFF,S. PERLIN, C. •ORNETSKY and S. S. KETV, Ann. N. Y. Acad. Sci. 66, 468 (1957). 11 D. H. INGVA~and U. SODERBERG,]~xperientia 12, 427 (1957). x~ N. J. GIARMAN, LSD, Man and Society (Weslyan, Middletown, Conn. 1967), p. 143. 18 Acknowledgements: We are especially grateful to Drs. ALBERT HOFMAN and AURELIO CERLETTI (Sandoz, Basel) for the gifts of LSD derivatives. This investigation was supported by Public Health Service Grant No. NS-05526 from the National Institute of Neurological Diseases and Stroke. 14 Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA. 15 Maryland Psychiatric Research Center, Box 3235, Baltimore, Maryland 21228, USA. ~6 Department of Pathophysiology, Medical Academy, G. Sofiiski St. Sofia 1, Bulgaria.
Inhibition of Prostaglandin Synthetase by Psychotropic Drugs A c c o r d i n g t o t h e h y p o t h e s i s a d v a n c e d b y VANE, t h e p h a r m a c o d y n a m i c a c t i v i t y of n o n - s t e r o i d a l a n t i - i n f l a m m a t o r y a g e n t s (NSAA's) is a t t r i b u t a b l e to t h e i n h i b i t i o n of p r o s t a g l a n d i n (PG) s y n t h e t a s e l - a . I t t h e r e f o r e s e e m e d of i n t e r e s t to d e t e r m i n e w h e t h e r t h i s effect is p e c u l i a r t o t h i s class of c o m p o u n d s . W i t h t h i s end in view, a n d in t h e l i g h t of r e c e n t l y p u b l i s h e d o b s e r v a t i o n s i n d i c a t i n g t h a t c e r t a i n p s y c h o t r o p i c a g e n t s m a y i n t e r f e r e w i t h P G synthesis 4, 5, we u n d e r t o o k e x p e r i m e n t s t o find o u t w h e t h e r c o m p o u n d s possessing n e u r o l e p t i c , a n t i d e p r e s s a n t a n d / o r t r a n q u i l l i z i n g properties, i n h i b i t P G s y n t h e t a s e in vitro. Material and methods. T h e e n z y m a t i c a s s a y was carried o u t a c c o r d i n g t o a m o d i f i c a t i o n of t h e t e c h n i q u e described b y TAKEGUCHI et a1.% T h e i n c u b a t i o n m e d i u m c o n t a i n e d 3 m g of t h e lyophilized m i c r o s o m a l f r a c t i o n of b o v i n e s e m i n a l Vesicle as enzyme, 0.33 tzM 14C-labelled arachidonic acid (spec. a c t i v i t y : 58 m C i / m M ) a n d 9.85 ~ M u n l a b e l l e d a r a c h i d o n i c acid as s u b s t r a t e , a n d 2.95 m M
1-adrenaline a n d 2.93 m M r e d u c e d 1-glutathione as cofactors in 5 m l Tris b u f f e r a t p H 8.3. E a c h of t h e comp o u n d s t e s t e d was a d d e d t o t h e r e a c t i o n m i x t u r e in t h r e e d i f f e r e n t c o n c e n t r a t i o n s . A f t e r i n c u b a t i o n for 30 min, t h e r e a c t i o n was s t o p p e d b y t h e a d d i t i o n of one d r o p of c o n c e n t r a t e d h y d r o c h l o r i c acid, a n d t h e lipid f r a c t i o n ext r a c t e d twice w i t h e t h y l a c e t a t e a n d s e p a r a t e d b y t h i n -
1 j. R. VANE, Nature, New Biol. 231, 232 (1971). z j. R. VANE, in Inflammation, Meeha~cisms and Control (Ed. I. H. LEPow and P. A. WARD; Academic Press, New York and London 1972), p. 261. S. H. FERREIRA and J. R. VANE, A. Rev. Pharmac. 7d, 57 (1974). 4 R. E. LEE, Prostaglandins 5, 63 (1974). a E. C. Ku, J. M. WASVARYand W. D. CAs~t, personal communication. 6 C. TAKEOUCm, E. KOHNO and C. J. SI~, Biochemistry 10, 2372 (1971).
15. 3. 1975
Specialia
Inhibition of PG-synthetase by psychotropic drugs (Interpolated values; (IDa0 and Ki; n ~ 9 per drug) Preparation
IDs0 (~zg/ml)
Chlorpromazine Clomipramine (1) Maprotiline (2) Benzoctamine (3) Amitriptyline Desipramine (4) Imipramine (5) Haloperidol
Ki (mM)
46 52 95 110 155 165 280 >300
Registered names: (1) Anafranil| (4) Pertofran| (5) Tofranil|
1.3 1.5 2.7 3.4 4.9 5.5 8.8 >7.3 (2) Ludiomil|
• • • • • • • •
10-i 10-i 10 i 10-1 10-~ 10 i 10-1 10 1
(3)Tacitin|
l a y e r c h r o m a t o g r a p h y 7. T h e zone on t h e c h r o m a t o g r a m c o r r e s p o n d i n g to P G E was s c r a p e d off, t h e s u b s t a n c e e x t r a c t e d once a g a i n a n d t h e r a d i o a c t i v i t y p r e s e n t det e r m i n e d in a liquid s c i n t i l l a t i o n c o u n t e r . I n p r e l i m i n a r y experiments, it had been shown that the radioactivity d e t e c t e d was a t t r i b u t a b l e to t h e P G E 2 formed, a n d t h a t t h e k i n e t i c s of t h e e n z y m e a s s a y c o n f o r m to t h e MichaelisM e n t e n e q u a t i o n w i t h / < m of 2.2 x 10 .5 M . Results. As is e v i d e n t f r o m t h e Table, all t h e p s y c h o t r o p i c a g e n t s t e s t e d i n h i b i t e d t h e c o n v e r s i o n of a r a c h i d o n i c acid to PGE2, a n d t h e degree of i n h i b i t i o n was r e l a t e d to t h e c o n c e n t r a t i o n s used. T h e m o s t p o t e n t were t h e tricyclic c o m p o u n d s c h l o r p r o m a z i n e a n d c l o m i p r a mine, followed b y t h e e t h a n e a n t h r a c e n e d e r i v a t i v e s m a p r o t i l i n e a n d b e n z o c t a m i n e . T h e tricyclic a n t i d e p r e s s a n t s a m i t r i p t y l i n e , d e s i p r a m i n e a n d i m i p r a m i n e were less active, a n d h a l o p e r i d o l , w h i c h is a b u t y r o p h e n o n e derivative and hence structurally quite different from the
Kinetics of Inhibition 10 5 cpm
-- -40 &Z& 285VM 86 IJM
/
331
o t h e r d r u g s studied, h a d o n l y a v e r y s l i g h t effect. Gener a l l y speaking, t h e o r d e r of a c t i v i t y d i s p l a y e d b y t h e s e c o m p o u n d s was c o m p a r a b l e w i t h t h a t of t h e N S A A p h e n y l b u t a z o n e , w h i c h in a c o n c e n t r a t i o n of a p p r o x i m a t e l y 0.5 m M i n h i b i t s t h e s y n t h e s i s of P G E 2 in t h i s t e s t s y s t e m to t h e e x t e n t of a b o u t 5 0 % s. T h e k i n e t i c s of t h e i n h i b i t o r y a c t i o n of m a p r o t i l i n e were e x a m i n e d nlore closely; t h e effects of t h i s p r e p a r a t i o n a t v a r i o u s c o n c e n t r a t i o n s o n t h e r a t e of s y n t h e s i s were determined at different substrate concentrations. From t h e results s h o w n in t h e Figure, it is clear t h a t t h e i n h i b i t i o n was c o m p e t i t i v e to t h e s u b s t r a t e . Discussion. T h e results o b t a i n e d clearly i n d i c a t e t h a t i n h i b i t i o n of P G s y n t h e t a s e is n o t a p h g r m a c o d y n a m i c a c t i o n p e c u l i a r t o c o m p o u n d s b e l o n g i n g to t h e class of N SAA's. As h a s a l r e a d y b e e n r e p o r t e d b y o t h e r a u t h o r s ~, 5, p s y c h o t r o p i c a g e n t s also h a v e t h i s effect. T h e fact t h a t FLOWER 9 d i d n o t o b s e r v e a n y i n h i b i t o r y a c t i o n of chlorp r o m a z i n e on t h i s e n z y m e m a y b e d u e to differences in t h e isolation p r o c e d u r e a n d i n c u b a t i o n c o n d i t i o n s . T h e f i n d i n g s described are i n t e r e s t i n g in v a r i o u s respects. I n t h e first place, t h e r e s u l t s a t l e a s t p a r t l y explain the anti-inflammatory activity shown by certain of t h e s e p r e p a r a t i o n s , i.e. b y b e n z o c t a m i n e 1~ a n d chlorp r o m a z i n e i 0 , ii in a n i m a l s , a n d b y i m i p r a m i n e 12 in m a n also. Secondly, t h e r e is a p o s s i b i l i t y t h a t t h e o b s e r v e d i n h i b i t o r y effect m i g h t also h a v e a s i g n i f i c a n t b e a r i n g a b o v e all o n t h e a n t i d e p r e s s a n t a c t i v i t y of t h e s e comp o u n d s : o n t h e one h a n d , t h e P G s released a t a d r e n e r g i c s y n a p s e s r e d u c e t h e l i b e r a t i o n of t h e t r a n s m i t t e r subs t a n c e s la, a4; o n t h e o t h e r h a n d , since t h e a c t i o n of a n t i d e p r e s s a n t s is a s c r i b e d t o a n increase i n t h e c o n c e n t r a t i o n of t r a n s m i t t e r s u b s t a n c e s a t t h e p o s t s y n a p t i c m e m b r a n e i5, i n h i b i t i o n of P G s y n t h e t a s e could c o n t r i b u t e t o w a r d s t h i s effect. F i n a l l y , t h e f a c t t h a t a s u b s t a n c e s u c h as haloperidol w i t h a d i s t i n c t l y n e u r o l e p t i c a c t i o n h a s scarcely a n y influence on P G s y n t h e s i s suggests t h a t i n t e r f e r e n c e w i t h P G s is n o t a crucially i m p o r t a n t f a c t o r in t h i s psychotropic activity.
Zusammen/assung. P s y c h o p h a r m a k a m i t n e u r o l e p t i scher, a n t i d e p r e s s i v e r u n d / o d e r t r a n q u i i l i s i e r e n d e r W i r kung, die eine t r i z y k l i s c h e S t r u k t u r besitzen, h e m m e n in v i t r o d o s i s a b h g n g i g die P r o s t a g l a n d i n - S y n t h e t a s e , welche aus O c h s e n s a m e n b l a s e isoliert wurde. H i n g e g e n weist das N e u r o l e p t i k u m Hgloperidol, das sich s t r u k t u r e l l y o n d e n anderen untersuchten Pr~tparaten wesentlich unterscheidet, k a u m e i n e n solchen E f f e k t auf. Die p h a r m a k o iogische B e d e u t u n g dieser B e f u n d e wird d i s k u t i e r t .
/ /
~wnoU~uj ~ 30 9 9 571.
P. KRUPP a n d M. WEsP
Research Department, Pharmaceuticals Division, Ciba-Geigy Limited, CH-dO02 Basel (Switzerland), 5 August 7974.
7 K. s p. 9 R. 10 R.
GREEN and B. SAMUELSSON, J . Lipid Res. 5, 117 (1964). KRUPP, B. EXER, R. MENASSs and R. ZIEL, in preparation. J. FLOWER, Pharmac. Rev. 26, 33 (1974). JAQOES and L. RIESTERRR, Pharmacol. 6, 29 (1971).
11 IV[. ROCHA E SILVA a n d J . GARClA LEME, in Chemical Mediators o]
0"068 0,101
0,2041/~S] (S=j~M Arachidonic Acid)
Kinetics of the inhibitory action of maprotiline on prostaglandin synthesis (double reciprocal plot).
the Acute Inflammatory Reaction (Pergamon Press, London 1973), p. 76. 12 M. D. SCOTT, Practitioner 202, 802 (1969). is L. STJXRNE, Acta physiol, seand. 86, 388 (1972). 14 p. HEDQVIST, in Advances in the Biosciences, Suppl. (Eds. S. BEROSTR6r~ and S. BERNARD; Pergamon Press, London 1973), Vol. 9, p. 75. 15 F. SULSER and E. SANDERS-BusH, A. Rev. Pharmae. lJ, 209 (1971).
Speeialia
s u b c o r t i c a I s t r u c t u r e s were affected significantly. Thus, t h e gross b e h a v i o r a l a l t e r a t i o n s were p r e c e d e d b y c h a n g e s in regional perfusion, w h i c h b e c a m e less v a r i a b l e a n d m o r e p r o n o u n c e d w i t h time. B l o o d gases were u n a f f e c t e d a t 10 m i n a f t e r i n j e c t i o n of L S D a l t h o u g h a slight h y p o x i a was o b s e r v e d b y 20 rain. L S D derivatives - Table I I. T h e 2 - m e t h y l - L S D , 6 - n o r - L S D a n d As,9-LSD d e r i v a t i v e s failed to a l t e r r a t b e h a v i o r in a n y o b s e r v a b l e w a y a t a dose level w h i c h was m a r k e d l y effective in t h e case of L S D ; in a d d i t i o n a l s u b g r o u p s of a n i m a l s b e h a v i o r a l effects were n o t d e t e c t e d b e y o n d 40 m i n a f t e r i.v. injection. F u r t h e r m o r e , t h e 2m e t h y l a n d A s,9 d e r i v a t i v e s also failed to a l t e r b l o o d p r e s s u r e or cardiac o u t p u t s . T h e 6-nor-LSD, h o w e v e r , a p p e a r e d m o r e p o t e n t in m i m i c k i n g t h e p e r i p h e r a l effects of L S D b y e l e v a t i n g a r t e r i a l pressures b y a b o u t 40 m m H g a b o v e m e a n pressures a n d s i g n i f i c a n t l y r e d u c i n g c a r d i a c o u t p u t s b y 25~o. N o n e of t h e s e c o m p o u n d s affected regional p e r f u s i o n of t h e b r a i n , w i t h t h e possible e x c e p t i o n of 2 - m e t h y l L S D w h i c h caused a fall in olf a c t o r y b u l b flow. Discussion. T h e flo%v c h a n g e s t o t h e p a r i e t a l a n d f r o n t a l cortex, cerebellar and, p e r h a p s , t h e dorsal h i p p o c a m p a l regions a p p e a r t o b e r e l a t e d to t h e b e h a v i o r a l effects. T h e f i n d i n g s w i t h 2 - m e t h y l L S D , 6-nor L S D , a n d A s, 9 L S D to w h i c h r a t s are n o t v i s i b l y responsive, r e v e a l no c h a n g e s in r e g i o n a l p e r f u s i o n of t h e brain, a l t h o u g h some of t h e s e compounds have considerable peripheral cardiovascular effects (Table II). A s s u m i n g as o t h e r do 8-s t h e n , t h a t regional b l o o d flow in t h e b r a i n is s e c o n d a r y to f u n c t i o n , t h e m o s t p a r s i m o n i o u s e x p l a n a t i o n for t h e s e f i n d i n g s is t h a t t h e flow c h a n g e s signal n e t increases in t h e a c t i v i t i e s of t h e p a r i e t a l , frontal, a n d cerebellar coreices of t h e r a t a t t h e s a m e t i m e t h a t some f u n c t i o n s of t h e dorsal h i p p o c a m p u s p e r h a p s decrease. I n p a s t studies in conscious men~~ a n d a n e s t h e t i z e d cats ~ gross c e r e b r a l perfusion appeared unchanged by LSD administration. T h a t L S D , indeed, increased t h e flow of b l o o d to c e r t a i n areas of t h e b r a i n s of conscious r a t s e m p h a s i z e s o u r c o n t e n t i o n t h a t t h e s e r e l a t i v e l y r e s t r i c t e d r e s p o n s e s were t h e r e s u l t of tissue a c t i v i t y responses likely to b e o b s c u r e d b y whole b r a i n m e a s u r e m e n t s or t h e use of a n e s t h e t i c s 9 A l t h o u g h t h e c h a n g e s in regional p e r f u s i o n of t h e b r a i n m a y signal c h a n g e s in function, t h e p r i m a r y sites of a c t i o n of L S D r e m a i n obscure. Some regions w h i c h r e t a i n r a d i o l a b e l l e d L S D h a v e b e e n i n t e r p r e t e d as possible sites
EXPERIE NTIA31/3
of a c t i o n ~. T h u s , a c c u m u l a t i o n s of L S D i n t h o s e m e s e n cephalic a n d d i e n c e p h a l i c s t r u c t u r e s a s s o c i a t e d w i t h a u t o n o m i c c e n t e r s in t h e b r a i n c o r r e l a t e well w i t h t h e c e n t r a l l y m e d i a t e d a u t o n o m i c effects of t h e d r u g ~. A l t h o u g h L S D also b i n d s s e l e c t i v e l y to a m i n o r i t y of cells in f r o n t a l c o r t e x a n d c e r e b e l l u m t, 2, regions t o w h i c h t h e flow of b l o o d also is increased, t h e w i d e s p r e a d u p t a k e s of L S D in m a n y s u b c o r t i c a l areas are n o t p a r a l l e l e d b y flow changes. A l o n g w i t h ~he a c k n o w l e d g e d effects in subcortical regions t h e n , t h e flow d a t a suggest t h a t some cortical regions a n d c e r e b e l l u m also are r e s p o n s i v e to L S D . A t t h i s time, h o w e v e r , it is inlpossible to d i s t i n g u i s h b e t w e e n s e c o n d a r y f u n c t i o n a l a s p e c t s a n d p r i m a r y sites of d r u g a c t i o n ~3.
Zusammen/assung. Die i.v. V e r a b r e i c h u n g y o n L S D a n R a t t e n s t e i g e r t d e n B l u t k r e i s l a u f i m H i r n s t a m m sowie i m f r o n t a l e n u n d p a r i e t a l e n C o r t e x selektiv. E s w u r d e n d u r c h 6 - N o r - L S D , 2 - M e t h y l - L S D u n d Ao,9-LSD w e d e r w a h r n e h m b a r e V e r h a l t e n s ~ n d e r u n g e n n o c h A n d e r u n g e n des regionalen Blutkreislaufs verursacht. H. GOLDMAN 14, ]~. FISCHER 15, N. NICOLOV 16 a n d S. MURPHY 14
Department o~ Pharmacology, Wayne State University School of Medicine, 5dO East Can/ield A venue, Detroit (Michigan 48201, U S A ) , 9 September 7974.
10 L. SOKOLOFF,S. PERLIN, C. •ORNETSKY and S. S. KETV, Ann. N. Y. Acad. Sci. 66, 468 (1957). 11 D. H. INGVA~and U. SODERBERG,]~xperientia 12, 427 (1957). x~ N. J. GIARMAN, LSD, Man and Society (Weslyan, Middletown, Conn. 1967), p. 143. 18 Acknowledgements: We are especially grateful to Drs. ALBERT HOFMAN and AURELIO CERLETTI (Sandoz, Basel) for the gifts of LSD derivatives. This investigation was supported by Public Health Service Grant No. NS-05526 from the National Institute of Neurological Diseases and Stroke. 14 Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA. 15 Maryland Psychiatric Research Center, Box 3235, Baltimore, Maryland 21228, USA. ~6 Department of Pathophysiology, Medical Academy, G. Sofiiski St. Sofia 1, Bulgaria.
Inhibition of Prostaglandin Synthetase by Psychotropic Drugs A c c o r d i n g t o t h e h y p o t h e s i s a d v a n c e d b y VANE, t h e p h a r m a c o d y n a m i c a c t i v i t y of n o n - s t e r o i d a l a n t i - i n f l a m m a t o r y a g e n t s (NSAA's) is a t t r i b u t a b l e to t h e i n h i b i t i o n of p r o s t a g l a n d i n (PG) s y n t h e t a s e l - a . I t t h e r e f o r e s e e m e d of i n t e r e s t to d e t e r m i n e w h e t h e r t h i s effect is p e c u l i a r t o t h i s class of c o m p o u n d s . W i t h t h i s end in view, a n d in t h e l i g h t of r e c e n t l y p u b l i s h e d o b s e r v a t i o n s i n d i c a t i n g t h a t c e r t a i n p s y c h o t r o p i c a g e n t s m a y i n t e r f e r e w i t h P G synthesis 4, 5, we u n d e r t o o k e x p e r i m e n t s t o find o u t w h e t h e r c o m p o u n d s possessing n e u r o l e p t i c , a n t i d e p r e s s a n t a n d / o r t r a n q u i l l i z i n g properties, i n h i b i t P G s y n t h e t a s e in vitro. Material and methods. T h e e n z y m a t i c a s s a y was carried o u t a c c o r d i n g t o a m o d i f i c a t i o n of t h e t e c h n i q u e described b y TAKEGUCHI et a1.% T h e i n c u b a t i o n m e d i u m c o n t a i n e d 3 m g of t h e lyophilized m i c r o s o m a l f r a c t i o n of b o v i n e s e m i n a l Vesicle as enzyme, 0.33 tzM 14C-labelled arachidonic acid (spec. a c t i v i t y : 58 m C i / m M ) a n d 9.85 ~ M u n l a b e l l e d a r a c h i d o n i c acid as s u b s t r a t e , a n d 2.95 m M
1-adrenaline a n d 2.93 m M r e d u c e d 1-glutathione as cofactors in 5 m l Tris b u f f e r a t p H 8.3. E a c h of t h e comp o u n d s t e s t e d was a d d e d t o t h e r e a c t i o n m i x t u r e in t h r e e d i f f e r e n t c o n c e n t r a t i o n s . A f t e r i n c u b a t i o n for 30 min, t h e r e a c t i o n was s t o p p e d b y t h e a d d i t i o n of one d r o p of c o n c e n t r a t e d h y d r o c h l o r i c acid, a n d t h e lipid f r a c t i o n ext r a c t e d twice w i t h e t h y l a c e t a t e a n d s e p a r a t e d b y t h i n -
1 j. R. VANE, Nature, New Biol. 231, 232 (1971). z j. R. VANE, in Inflammation, Meeha~cisms and Control (Ed. I. H. LEPow and P. A. WARD; Academic Press, New York and London 1972), p. 261. S. H. FERREIRA and J. R. VANE, A. Rev. Pharmac. 7d, 57 (1974). 4 R. E. LEE, Prostaglandins 5, 63 (1974). a E. C. Ku, J. M. WASVARYand W. D. CAs~t, personal communication. 6 C. TAKEOUCm, E. KOHNO and C. J. SI~, Biochemistry 10, 2372 (1971).
15. 3. 1975
Specialia
Inhibition of PG-synthetase by psychotropic drugs (Interpolated values; (IDa0 and Ki; n ~ 9 per drug) Preparation
IDs0 (~zg/ml)
Chlorpromazine Clomipramine (1) Maprotiline (2) Benzoctamine (3) Amitriptyline Desipramine (4) Imipramine (5) Haloperidol
Ki (mM)
46 52 95 110 155 165 280 >300
Registered names: (1) Anafranil| (4) Pertofran| (5) Tofranil|
1.3 1.5 2.7 3.4 4.9 5.5 8.8 >7.3 (2) Ludiomil|
• • • • • • • •
10-i 10-i 10 i 10-1 10-~ 10 i 10-1 10 1
(3)Tacitin|
l a y e r c h r o m a t o g r a p h y 7. T h e zone on t h e c h r o m a t o g r a m c o r r e s p o n d i n g to P G E was s c r a p e d off, t h e s u b s t a n c e e x t r a c t e d once a g a i n a n d t h e r a d i o a c t i v i t y p r e s e n t det e r m i n e d in a liquid s c i n t i l l a t i o n c o u n t e r . I n p r e l i m i n a r y experiments, it had been shown that the radioactivity d e t e c t e d was a t t r i b u t a b l e to t h e P G E 2 formed, a n d t h a t t h e k i n e t i c s of t h e e n z y m e a s s a y c o n f o r m to t h e MichaelisM e n t e n e q u a t i o n w i t h / < m of 2.2 x 10 .5 M . Results. As is e v i d e n t f r o m t h e Table, all t h e p s y c h o t r o p i c a g e n t s t e s t e d i n h i b i t e d t h e c o n v e r s i o n of a r a c h i d o n i c acid to PGE2, a n d t h e degree of i n h i b i t i o n was r e l a t e d to t h e c o n c e n t r a t i o n s used. T h e m o s t p o t e n t were t h e tricyclic c o m p o u n d s c h l o r p r o m a z i n e a n d c l o m i p r a mine, followed b y t h e e t h a n e a n t h r a c e n e d e r i v a t i v e s m a p r o t i l i n e a n d b e n z o c t a m i n e . T h e tricyclic a n t i d e p r e s s a n t s a m i t r i p t y l i n e , d e s i p r a m i n e a n d i m i p r a m i n e were less active, a n d h a l o p e r i d o l , w h i c h is a b u t y r o p h e n o n e derivative and hence structurally quite different from the
Kinetics of Inhibition 10 5 cpm
-- -40 &Z& 285VM 86 IJM
/
331
o t h e r d r u g s studied, h a d o n l y a v e r y s l i g h t effect. Gener a l l y speaking, t h e o r d e r of a c t i v i t y d i s p l a y e d b y t h e s e c o m p o u n d s was c o m p a r a b l e w i t h t h a t of t h e N S A A p h e n y l b u t a z o n e , w h i c h in a c o n c e n t r a t i o n of a p p r o x i m a t e l y 0.5 m M i n h i b i t s t h e s y n t h e s i s of P G E 2 in t h i s t e s t s y s t e m to t h e e x t e n t of a b o u t 5 0 % s. T h e k i n e t i c s of t h e i n h i b i t o r y a c t i o n of m a p r o t i l i n e were e x a m i n e d nlore closely; t h e effects of t h i s p r e p a r a t i o n a t v a r i o u s c o n c e n t r a t i o n s o n t h e r a t e of s y n t h e s i s were determined at different substrate concentrations. From t h e results s h o w n in t h e Figure, it is clear t h a t t h e i n h i b i t i o n was c o m p e t i t i v e to t h e s u b s t r a t e . Discussion. T h e results o b t a i n e d clearly i n d i c a t e t h a t i n h i b i t i o n of P G s y n t h e t a s e is n o t a p h g r m a c o d y n a m i c a c t i o n p e c u l i a r t o c o m p o u n d s b e l o n g i n g to t h e class of N SAA's. As h a s a l r e a d y b e e n r e p o r t e d b y o t h e r a u t h o r s ~, 5, p s y c h o t r o p i c a g e n t s also h a v e t h i s effect. T h e fact t h a t FLOWER 9 d i d n o t o b s e r v e a n y i n h i b i t o r y a c t i o n of chlorp r o m a z i n e on t h i s e n z y m e m a y b e d u e to differences in t h e isolation p r o c e d u r e a n d i n c u b a t i o n c o n d i t i o n s . T h e f i n d i n g s described are i n t e r e s t i n g in v a r i o u s respects. I n t h e first place, t h e r e s u l t s a t l e a s t p a r t l y explain the anti-inflammatory activity shown by certain of t h e s e p r e p a r a t i o n s , i.e. b y b e n z o c t a m i n e 1~ a n d chlorp r o m a z i n e i 0 , ii in a n i m a l s , a n d b y i m i p r a m i n e 12 in m a n also. Secondly, t h e r e is a p o s s i b i l i t y t h a t t h e o b s e r v e d i n h i b i t o r y effect m i g h t also h a v e a s i g n i f i c a n t b e a r i n g a b o v e all o n t h e a n t i d e p r e s s a n t a c t i v i t y of t h e s e comp o u n d s : o n t h e one h a n d , t h e P G s released a t a d r e n e r g i c s y n a p s e s r e d u c e t h e l i b e r a t i o n of t h e t r a n s m i t t e r subs t a n c e s la, a4; o n t h e o t h e r h a n d , since t h e a c t i o n of a n t i d e p r e s s a n t s is a s c r i b e d t o a n increase i n t h e c o n c e n t r a t i o n of t r a n s m i t t e r s u b s t a n c e s a t t h e p o s t s y n a p t i c m e m b r a n e i5, i n h i b i t i o n of P G s y n t h e t a s e could c o n t r i b u t e t o w a r d s t h i s effect. F i n a l l y , t h e f a c t t h a t a s u b s t a n c e s u c h as haloperidol w i t h a d i s t i n c t l y n e u r o l e p t i c a c t i o n h a s scarcely a n y influence on P G s y n t h e s i s suggests t h a t i n t e r f e r e n c e w i t h P G s is n o t a crucially i m p o r t a n t f a c t o r in t h i s psychotropic activity.
Zusammen/assung. P s y c h o p h a r m a k a m i t n e u r o l e p t i scher, a n t i d e p r e s s i v e r u n d / o d e r t r a n q u i i l i s i e r e n d e r W i r kung, die eine t r i z y k l i s c h e S t r u k t u r besitzen, h e m m e n in v i t r o d o s i s a b h g n g i g die P r o s t a g l a n d i n - S y n t h e t a s e , welche aus O c h s e n s a m e n b l a s e isoliert wurde. H i n g e g e n weist das N e u r o l e p t i k u m Hgloperidol, das sich s t r u k t u r e l l y o n d e n anderen untersuchten Pr~tparaten wesentlich unterscheidet, k a u m e i n e n solchen E f f e k t auf. Die p h a r m a k o iogische B e d e u t u n g dieser B e f u n d e wird d i s k u t i e r t .
/ /
~wnoU~uj ~ 30 9 9 571.
P. KRUPP a n d M. WEsP
Research Department, Pharmaceuticals Division, Ciba-Geigy Limited, CH-dO02 Basel (Switzerland), 5 August 7974.
7 K. s p. 9 R. 10 R.
GREEN and B. SAMUELSSON, J . Lipid Res. 5, 117 (1964). KRUPP, B. EXER, R. MENASSs and R. ZIEL, in preparation. J. FLOWER, Pharmac. Rev. 26, 33 (1974). JAQOES and L. RIESTERRR, Pharmacol. 6, 29 (1971).
11 IV[. ROCHA E SILVA a n d J . GARClA LEME, in Chemical Mediators o]
0"068 0,101
0,2041/~S] (S=j~M Arachidonic Acid)
Kinetics of the inhibitory action of maprotiline on prostaglandin synthesis (double reciprocal plot).
the Acute Inflammatory Reaction (Pergamon Press, London 1973), p. 76. 12 M. D. SCOTT, Practitioner 202, 802 (1969). is L. STJXRNE, Acta physiol, seand. 86, 388 (1972). 14 p. HEDQVIST, in Advances in the Biosciences, Suppl. (Eds. S. BEROSTR6r~ and S. BERNARD; Pergamon Press, London 1973), Vol. 9, p. 75. 15 F. SULSER and E. SANDERS-BusH, A. Rev. Pharmae. lJ, 209 (1971).
