314
Specialia
s i m i l a r p h e n o m e n o n h a s a l s o b e e n d e s c r i b e d in b a t s L A s s u m i n g t h i s c o m p a r i s o n is justified, it m a y b e c o n c l u d e d t h a t t h e ' a r o u s a l cycle' h a s a Q10 e q u a l to 1 a n d is a n e n d o g e n o u s r h y t h m little i n f l u e n c e d b y t h e e n v i r o m n e n t . T h e a b s e n c e of a n y r e l a t i o n s h i p b e t w e e n t h e leveI of m e t a b o l i s m a n d t h e s e cyclic p h e n o m e n a , t h e fact t h a t t h e sleep cycle is a l m o s t i d e n t i c a l w i t h t h a t of t h e guineapig (16 rain), a n d t h e s m a l l coefficient of v a r i a t i o n of t h e cycle a t 13 ~ suggest t h a t t h e l e n g t h of t h e sleep cycle is m o r e r e l a t e d t o t h e i n d e x of e n c e p h a l i z a t i o n 8 t h a n t o m e t a b o l i c rate.
m n ) d u r a n t 1'6t6 est tr6s p r o c h e de celle d u cycle d ' 6 v e i l (18,9 = 1,1 m n ) p e n d a n t l ' h i v e r . C e t t e a n a l o g i e est e n f a v e u r d u c a r a c t 6 r e p u r e m e n t e n d o g 6 n e d ' u n tel r y t h m e . P. L. TOUTAIN
and
Y. RUCKEBUSCH
9
Laboratoire de Physiologie, Ecole Nationale Vdtdrinaire, 23, chemin des Capelles, F-37076 Toulouse Cede, (France), 17 July 197d.
v D. R. BREBBIAand E. T. PVNE, Psychophysiology 9, 122 (1972). 8 A. DALLAIRE, P.' L. TOUTAIN and Y. RUCKEBUSCH, Physiol. Bebav. 13, 395 (1974). 9 Supported by grant from the Minist~re de l'Agrieulture (DGEER).
Rdsumd. L ' 6 t u d e des 6 t a t s de vigilance chez le h 6 r i s s o n (E. europeanus) g la t e m p 6 r a t u r e c e n t r a l e de 34~ et de 13~
EXPERIENTIA 31/3
m o n t r e que la dur6e du cycle de s o m m e i l (17,0 • 3,7
Artificial Lung Ventilation During Diaphragmatic Paralysis Section of one p h r e n i c n e r v e increases t h e a c t i v i t y of tile r e s p i r a t o r y centre. A c c o r d i n g t o DOLIVO 1, t h e r e a s o n for t h i s p h e n o m e n o n is t h e following: w h e n h a l f of t h e d i a p h r a g m is p a r a l y z e d t h e r e s p i r a t o r y v o l u m e of t h e l u n g s also decreases, a n d in t h i s w a y t h e i n h i b i t o r y reflex f r o m t h e l u n g s o n t h e r e s p i r a t o r y c e n t r e diminishes. Actually, artificial r e s p i r a t i o n w i t h a c o n s t a n t l u n g v o l u m e in a r a b b i t w i t h a n open c h e s t p r e v e n t s t h e increase of t h e a c t i v i t y of t h e r e s p i r a t o r y c e n t r e e v o k e d b y t h e section of t h e p h r e n i c nerve. B u t , as s h o w n in t h e p r e s e n t p a p a e r , a c o n s t a n t artificial r e s p i r a t i o n w h e n t h e c h e s t is i n t a c t ( t h a t is in c o n d i t i o n s i n w h i c h artificial r e s p i r a t i o n is m a d e d u r i n g r e a n i m a t i o n in p a t i e n t s w i t h p a r a l y s i s of t h e r e s p i r a t o r y muscles) does n o t p r e v e n t t h e increase of t h e a c t i v i t y of t h e r e s p i r a t o r y centre. U n d e r t h e s e conditions, besides t h e reflex f r o m t h e lungs, t h e a c c u m u l a t i o n of c a r b o n dioxide p l a y s a g r e a t role i n t h e increase of t h e a c t i v i t y of t h e r e s p i r a t o r y c e n t r e e v o k e d b y t h e p a r a l y s i s of t h e d i a p h r a g m . Methods. T h e e x p e r i m e n t s were p e r f o r m e d on 10 a d u l t r a b b i t s a n e s t h e t i z e d w i t h 30-40 m g / k g N e m b u t a l . A f t e r t r a c h e o t o m y t h e r e s p i r a t o r y f r e q u e n c y (F) a n d • tidal v o l u m e (Vt) were m e a s u r e d a n d t h e n t h e a n i m a l s were s u b j e c t e d t o p a s s i v e v e n t i l a t i o n in w h i c h t h e f r e q u e n c y a n d t h e v o l u m e of t h e r e s p i r a t o r y p u m p coincide w i t h t h e s a m e p a r a m e t r e s of s p o n t a n e o u s r e s p i r a t i o n . Section of t h e p h r e n i c n e r v e s was p e r f o r m e d a t a low level in t h e neck, j u s t before t h e n e r v e s e n t e r t h e t h o r a c i c c a v i t y . E l e c t r o m i o g r a m s were r e c o r d e d b y b i p o l a r steel-wire electrodes affixed to t h e i n t e r c o s t a l muscles. B l o o d s a m p l e s were o b t a i n e d f r o m f e m o r a l arteries. B l o o d p H a n d PaCO~ m e a s u r e m e n t s were m a d e in m i c r o Astrup.
Results and discussion. One m i n a f t e r b i l a t e r a l s e c t i o n of t h e p h r e n i c nerves, t h e r e is a m a r k e d decrease of V t (from 12.0 t o 5.0 ml). C o r r e s p o n d i n g l y t h e p H decreases (from 7.32 • 0.04 t o 7.20 • 0.03) a n d t h e P a C O 2 increases (from 38.0 i 3.5 to 51 ~ 8.3) (Table I). Simult a n e o u s l y t h e electrical a c t i v i t y of t h e i n t e r c o s t a l muscles increases s h a r p l y (Figure). To n o r m a l i z e t h e PaCO~ a n d t h e EMG, one m u s t increase t h e v o l u m e of t h e r e s p i r a t o r y p u m p f r o m 12.0 t o 22.5 m l (Table II, Figure). If t h e p a s s i v e v e n t i l a t i o n was n o t increased, t h e a n i m a l s died in 0.5-1 h after bilateral phrenicotomy. T h u s t h e size of t h e passive v e n t i l a t i o n w h i c h satisfied a n i m a l s w i t h i n t a c t r e s p i r a t o r y muscles does n o t satisfy a n i m a l s w i t h d i a p h r a g m a t i c paralysis. D i a p h r a g m a t i c p a r a l y s i s in r a b b i t s leads to a decrease of l u n g c o m p l i a n c e , alveolar hypoventilation and hypercapnia. Thus not only t h e reflex f r o m t h e l u n g s b u t a c c u m u l a t i o n of c a r b o n dioxide p l a y s a g r e a t role in t h e increase of t h e a c t i v i t y of t h e e x t r a d i a p h r a g m a t i c muscles d u r i n g d i a p h r a g m a t i c paralysis. O n t h e basis of t h e s e o b s e r v a t i o n s , t h e following conclusions were r e a c h e d : 1. As is k n o w n , p a t i e n t s w i t h r e s p i r a t o r y p a r a l y s i s r e q u i r e artificial v e n t i l a t i o n w h i c h is m u c h g r e a t e r t h a n t h e v e n t i l a t i o n c a l c u l a t e d o n t h e
1M. DOLIVO, Helv. physiol, pharmae. Acta, 10, 366 (1952).
Table I. The influence of bilateral phrenieotomy on the respiration in rabbits Tidal volume (ml) Before Mean SD p n ~ io
•
12.0 2.4
After 5.0 =k0.5 0.001
Respiratory frequency (resp.'/min)
pH
Before
Before
46.0 ~15.0
After 46.0 ~15.0 0.5
7.32 +0.04
Pa CO2 (mm Hg) After 7.20 ~0.03 0.001
Before i
38.0 3.3
After 51.0 ~ 8.3 0.001
pHa, pH arterial blood; Pa CO2, partial pressure of carbon dioxide in arterial blood; Mean, mean values; SD, standard deviations; P, significance of differences from values for normal animals; n, number of animals.
15.3. 1975
Speeialia
315
Table II. The influence of artificial ventilation on pH and Pa CO~ in the phrenieotomized rabbits During the artificial ventilation which coincides with the respiratory frequency and tidal volume of the spontaneous breathing
The increase of the volume of the pump which was need to normalize pH and Pa CO s
Volume of the p u m p (ml) Mean 12.0 SD n = 10
Frequency of the p u m p
46.0 •
pH
Pa CO~ (mm Hg)
Volume of the pump (ml)
Frequency of the pump
7.24
48.5 •
22.5
46.0
pH
7.28 -t-0.01
Pa CO s (mm Hg) 38.0 4-3.5
See the glossary of abreviations in Table I.
b a s i s of n o m o g r a m s . P e r h a p s t h e i r d e m a n d d e p e n d s o n t h e d e c r e a s e of t h e l u n g c o m p l i a n c e a n d a l v e o l a r h y p o v e n t i l a t i o n e v o k e d b y p a r a l y s i s of t h e r e s p i r a t o r y m u s c l e s . 2. T h e r e a r e s o m e a t t e m p t s t o p r e v e n t b r e a t h l e s s n e s s b y m e a n s of a b l o c k of t h e p h r e n i c n e r v e s 2. A s is s t r e s s e d by the authors there was only a partial diaphragmatic p a r a l y s i s a f t e r t h e b l o c k . I t m a y b e t h o u g h t t h a t in t h e c a s e of t o t a l p a r a l y s i s of t h e d i a p h r a g m , t h i s m e t h o d m a y evoke a quite contrary result.
B b l B O J I b I . HeCMOTp9 Ha HcKyCCTBeHH0e c0xpaHeHHe HopManbHO.~ :t6r0qH0~ BeHTHJI~L1HH~ (1)peHHKOTOMHH BbI3bIaaeT y K p 0 ~ K O B pea~oe yBe~uqeHHe H a n p ~ e H H ~ CO s B Kp0BH. ~ J ~ B0CCTaHOBneHH~ H0pManbH0rO n a n p ~ e H a a C02 He06x0/IHM0 3HaqHTeJ1bH0 yBeJINqHTb ~F0qHy~O BeH"rHJI~ILHO. ~THM IIOBHJIHMOMy 0~%fiCHfleTCYtTO, qTO ~OJIbHMe c n a p a J m q o m RBIxaTeJIbHblX MbIIIItl Tpe6ymT y B e a g q e n u g JI~r0qH0~ BeHTHJIHIIHH, 3HaqUTe~bH0 lIpeBocxo/~gIIIe~ HopManbHym. S. I. FRANKSTEIN, T. I. SERGEEVA, Z. N. ~ERGEEVA a n d E . S. IVANOVA
The electrical activity from intercostal inspiratory muscles (the thin lines - integral activity of the same muscle). A) while the frequency and the volume of the respiratory pump coincides with the spontaneous breathing. Before phrenicotomy. B) the size of the artificial respiration remains the same as in A. After phrenieotomy strong increase of the electrical activity. C) While the volume of the respiratory pump was increased from 10 ml to 20 ml. The electrical activity is normalized.
Institute o/Normal and Pathological Physiology, Academy o/ Medical Sciences, Balti]skaya 8, Moshwa (USSR), 1 July 1974.
2 M. J. IV[. NOBLE, G. H. EISELE, D. TRENGHARD and A. Guz, Breathing: Hering-Breuer Centenary Symposium, London (J. and A. Churchill, London 1970), p. 233.
Age-Dependent Changes in (Na, K)-ATPase Activity in Brains of Mice Susceptible to Seizures M i c e of t h e D B A s t r a i n , s u s c e p t i b l e t o a t I d i o g e n i c s e i z u r e s , h a v e c o n v u l s i o n s a t t h e a g e of 30 d a y s w h e n t h e y a r e e x p o s e d t o h e a t , w h e r e a s m i c e of t h e C57 s t r a i n d o n o t 1. S i n c e D B A m i c e d o n o t h a v e c o n v u l s i o n s w i t h e l e v a t e d t e m p e r a t u r e a t 20 or a t 40 d a y s , t h e y s e e m t o b e a m o d e l of f e b r i l e c o n v u l s i o n s i n h u m a n s 1, a n d i n t e r e s t attaches to features that distinguish them from the s e i z u r e - r e s i s t a n t C57 s t r a i n . C u r i o u s l y e n o u g h t h e f i n d i n g s of ABOOD a n d GERARD ~ h a v e n e v e r b e e n c o n f i r m e d t h a t b r a i n s of D B A m i c e h a v e l o w e r A T P a s e a n d a l o w e r P / O r a t i o t h a n t h o s e of C57 m i c e a t t h e a g e of s e i z u r e s u s c e p t i b i l i t y b u t n o t b e f o r e or a f t e r . T h e a u t h o r s c o u l d n o t t h e n d i f f e r e n t i a t e t h e f o r m of A T P a s e ; it is n o w
k n o w n - - t h a t A T P a s e a c t i v i t y i n b r a i n is l a r g e l y i n t h e f o r m a c t i v a t e d ~by N a + a n d 1K+, i.e. (Na, K ) - A T P a s e a. For this reason I studied ATPase activity in microsomal m e m b r a n e s of b r a i n s of DTBA m i c e a t t h e a g e o f s u s c e p t i b i l i t y ; 30 d a y s ; a n d b e f o r e a n d a f t e r , a t 20 a n d 60 days. The results were compared with those of non1 L. HERTZ, A. SCHOUSBOE, B. FORMBY and M. LENNoz-BUCHTHAL, Epilepsia 75, 619 (1974). s L. G. ABOOD and R. W. GERARD, in Biochemistry o] the Developing Nervous System (Ed. H. WAELSCH; Academic Press, New York 1955). J. C. SKOU, Biochim. biophys. Acta 58, 314 (1962).
Specialia
s i m i l a r p h e n o m e n o n h a s a l s o b e e n d e s c r i b e d in b a t s L A s s u m i n g t h i s c o m p a r i s o n is justified, it m a y b e c o n c l u d e d t h a t t h e ' a r o u s a l cycle' h a s a Q10 e q u a l to 1 a n d is a n e n d o g e n o u s r h y t h m little i n f l u e n c e d b y t h e e n v i r o m n e n t . T h e a b s e n c e of a n y r e l a t i o n s h i p b e t w e e n t h e leveI of m e t a b o l i s m a n d t h e s e cyclic p h e n o m e n a , t h e fact t h a t t h e sleep cycle is a l m o s t i d e n t i c a l w i t h t h a t of t h e guineapig (16 rain), a n d t h e s m a l l coefficient of v a r i a t i o n of t h e cycle a t 13 ~ suggest t h a t t h e l e n g t h of t h e sleep cycle is m o r e r e l a t e d t o t h e i n d e x of e n c e p h a l i z a t i o n 8 t h a n t o m e t a b o l i c rate.
m n ) d u r a n t 1'6t6 est tr6s p r o c h e de celle d u cycle d ' 6 v e i l (18,9 = 1,1 m n ) p e n d a n t l ' h i v e r . C e t t e a n a l o g i e est e n f a v e u r d u c a r a c t 6 r e p u r e m e n t e n d o g 6 n e d ' u n tel r y t h m e . P. L. TOUTAIN
and
Y. RUCKEBUSCH
9
Laboratoire de Physiologie, Ecole Nationale Vdtdrinaire, 23, chemin des Capelles, F-37076 Toulouse Cede, (France), 17 July 197d.
v D. R. BREBBIAand E. T. PVNE, Psychophysiology 9, 122 (1972). 8 A. DALLAIRE, P.' L. TOUTAIN and Y. RUCKEBUSCH, Physiol. Bebav. 13, 395 (1974). 9 Supported by grant from the Minist~re de l'Agrieulture (DGEER).
Rdsumd. L ' 6 t u d e des 6 t a t s de vigilance chez le h 6 r i s s o n (E. europeanus) g la t e m p 6 r a t u r e c e n t r a l e de 34~ et de 13~
EXPERIENTIA 31/3
m o n t r e que la dur6e du cycle de s o m m e i l (17,0 • 3,7
Artificial Lung Ventilation During Diaphragmatic Paralysis Section of one p h r e n i c n e r v e increases t h e a c t i v i t y of tile r e s p i r a t o r y centre. A c c o r d i n g t o DOLIVO 1, t h e r e a s o n for t h i s p h e n o m e n o n is t h e following: w h e n h a l f of t h e d i a p h r a g m is p a r a l y z e d t h e r e s p i r a t o r y v o l u m e of t h e l u n g s also decreases, a n d in t h i s w a y t h e i n h i b i t o r y reflex f r o m t h e l u n g s o n t h e r e s p i r a t o r y c e n t r e diminishes. Actually, artificial r e s p i r a t i o n w i t h a c o n s t a n t l u n g v o l u m e in a r a b b i t w i t h a n open c h e s t p r e v e n t s t h e increase of t h e a c t i v i t y of t h e r e s p i r a t o r y c e n t r e e v o k e d b y t h e section of t h e p h r e n i c nerve. B u t , as s h o w n in t h e p r e s e n t p a p a e r , a c o n s t a n t artificial r e s p i r a t i o n w h e n t h e c h e s t is i n t a c t ( t h a t is in c o n d i t i o n s i n w h i c h artificial r e s p i r a t i o n is m a d e d u r i n g r e a n i m a t i o n in p a t i e n t s w i t h p a r a l y s i s of t h e r e s p i r a t o r y muscles) does n o t p r e v e n t t h e increase of t h e a c t i v i t y of t h e r e s p i r a t o r y centre. U n d e r t h e s e conditions, besides t h e reflex f r o m t h e lungs, t h e a c c u m u l a t i o n of c a r b o n dioxide p l a y s a g r e a t role i n t h e increase of t h e a c t i v i t y of t h e r e s p i r a t o r y c e n t r e e v o k e d b y t h e p a r a l y s i s of t h e d i a p h r a g m . Methods. T h e e x p e r i m e n t s were p e r f o r m e d on 10 a d u l t r a b b i t s a n e s t h e t i z e d w i t h 30-40 m g / k g N e m b u t a l . A f t e r t r a c h e o t o m y t h e r e s p i r a t o r y f r e q u e n c y (F) a n d • tidal v o l u m e (Vt) were m e a s u r e d a n d t h e n t h e a n i m a l s were s u b j e c t e d t o p a s s i v e v e n t i l a t i o n in w h i c h t h e f r e q u e n c y a n d t h e v o l u m e of t h e r e s p i r a t o r y p u m p coincide w i t h t h e s a m e p a r a m e t r e s of s p o n t a n e o u s r e s p i r a t i o n . Section of t h e p h r e n i c n e r v e s was p e r f o r m e d a t a low level in t h e neck, j u s t before t h e n e r v e s e n t e r t h e t h o r a c i c c a v i t y . E l e c t r o m i o g r a m s were r e c o r d e d b y b i p o l a r steel-wire electrodes affixed to t h e i n t e r c o s t a l muscles. B l o o d s a m p l e s were o b t a i n e d f r o m f e m o r a l arteries. B l o o d p H a n d PaCO~ m e a s u r e m e n t s were m a d e in m i c r o Astrup.
Results and discussion. One m i n a f t e r b i l a t e r a l s e c t i o n of t h e p h r e n i c nerves, t h e r e is a m a r k e d decrease of V t (from 12.0 t o 5.0 ml). C o r r e s p o n d i n g l y t h e p H decreases (from 7.32 • 0.04 t o 7.20 • 0.03) a n d t h e P a C O 2 increases (from 38.0 i 3.5 to 51 ~ 8.3) (Table I). Simult a n e o u s l y t h e electrical a c t i v i t y of t h e i n t e r c o s t a l muscles increases s h a r p l y (Figure). To n o r m a l i z e t h e PaCO~ a n d t h e EMG, one m u s t increase t h e v o l u m e of t h e r e s p i r a t o r y p u m p f r o m 12.0 t o 22.5 m l (Table II, Figure). If t h e p a s s i v e v e n t i l a t i o n was n o t increased, t h e a n i m a l s died in 0.5-1 h after bilateral phrenicotomy. T h u s t h e size of t h e passive v e n t i l a t i o n w h i c h satisfied a n i m a l s w i t h i n t a c t r e s p i r a t o r y muscles does n o t satisfy a n i m a l s w i t h d i a p h r a g m a t i c paralysis. D i a p h r a g m a t i c p a r a l y s i s in r a b b i t s leads to a decrease of l u n g c o m p l i a n c e , alveolar hypoventilation and hypercapnia. Thus not only t h e reflex f r o m t h e l u n g s b u t a c c u m u l a t i o n of c a r b o n dioxide p l a y s a g r e a t role in t h e increase of t h e a c t i v i t y of t h e e x t r a d i a p h r a g m a t i c muscles d u r i n g d i a p h r a g m a t i c paralysis. O n t h e basis of t h e s e o b s e r v a t i o n s , t h e following conclusions were r e a c h e d : 1. As is k n o w n , p a t i e n t s w i t h r e s p i r a t o r y p a r a l y s i s r e q u i r e artificial v e n t i l a t i o n w h i c h is m u c h g r e a t e r t h a n t h e v e n t i l a t i o n c a l c u l a t e d o n t h e
1M. DOLIVO, Helv. physiol, pharmae. Acta, 10, 366 (1952).
Table I. The influence of bilateral phrenieotomy on the respiration in rabbits Tidal volume (ml) Before Mean SD p n ~ io
•
12.0 2.4
After 5.0 =k0.5 0.001
Respiratory frequency (resp.'/min)
pH
Before
Before
46.0 ~15.0
After 46.0 ~15.0 0.5
7.32 +0.04
Pa CO2 (mm Hg) After 7.20 ~0.03 0.001
Before i
38.0 3.3
After 51.0 ~ 8.3 0.001
pHa, pH arterial blood; Pa CO2, partial pressure of carbon dioxide in arterial blood; Mean, mean values; SD, standard deviations; P, significance of differences from values for normal animals; n, number of animals.
15.3. 1975
Speeialia
315
Table II. The influence of artificial ventilation on pH and Pa CO~ in the phrenieotomized rabbits During the artificial ventilation which coincides with the respiratory frequency and tidal volume of the spontaneous breathing
The increase of the volume of the pump which was need to normalize pH and Pa CO s
Volume of the p u m p (ml) Mean 12.0 SD n = 10
Frequency of the p u m p
46.0 •
pH
Pa CO~ (mm Hg)
Volume of the pump (ml)
Frequency of the pump
7.24
48.5 •
22.5
46.0
pH
7.28 -t-0.01
Pa CO s (mm Hg) 38.0 4-3.5
See the glossary of abreviations in Table I.
b a s i s of n o m o g r a m s . P e r h a p s t h e i r d e m a n d d e p e n d s o n t h e d e c r e a s e of t h e l u n g c o m p l i a n c e a n d a l v e o l a r h y p o v e n t i l a t i o n e v o k e d b y p a r a l y s i s of t h e r e s p i r a t o r y m u s c l e s . 2. T h e r e a r e s o m e a t t e m p t s t o p r e v e n t b r e a t h l e s s n e s s b y m e a n s of a b l o c k of t h e p h r e n i c n e r v e s 2. A s is s t r e s s e d by the authors there was only a partial diaphragmatic p a r a l y s i s a f t e r t h e b l o c k . I t m a y b e t h o u g h t t h a t in t h e c a s e of t o t a l p a r a l y s i s of t h e d i a p h r a g m , t h i s m e t h o d m a y evoke a quite contrary result.
B b l B O J I b I . HeCMOTp9 Ha HcKyCCTBeHH0e c0xpaHeHHe HopManbHO.~ :t6r0qH0~ BeHTHJI~L1HH~ (1)peHHKOTOMHH BbI3bIaaeT y K p 0 ~ K O B pea~oe yBe~uqeHHe H a n p ~ e H H ~ CO s B Kp0BH. ~ J ~ B0CCTaHOBneHH~ H0pManbH0rO n a n p ~ e H a a C02 He06x0/IHM0 3HaqHTeJ1bH0 yBeJINqHTb ~F0qHy~O BeH"rHJI~ILHO. ~THM IIOBHJIHMOMy 0~%fiCHfleTCYtTO, qTO ~OJIbHMe c n a p a J m q o m RBIxaTeJIbHblX MbIIIItl Tpe6ymT y B e a g q e n u g JI~r0qH0~ BeHTHJIHIIHH, 3HaqUTe~bH0 lIpeBocxo/~gIIIe~ HopManbHym. S. I. FRANKSTEIN, T. I. SERGEEVA, Z. N. ~ERGEEVA a n d E . S. IVANOVA
The electrical activity from intercostal inspiratory muscles (the thin lines - integral activity of the same muscle). A) while the frequency and the volume of the respiratory pump coincides with the spontaneous breathing. Before phrenicotomy. B) the size of the artificial respiration remains the same as in A. After phrenieotomy strong increase of the electrical activity. C) While the volume of the respiratory pump was increased from 10 ml to 20 ml. The electrical activity is normalized.
Institute o/Normal and Pathological Physiology, Academy o/ Medical Sciences, Balti]skaya 8, Moshwa (USSR), 1 July 1974.
2 M. J. IV[. NOBLE, G. H. EISELE, D. TRENGHARD and A. Guz, Breathing: Hering-Breuer Centenary Symposium, London (J. and A. Churchill, London 1970), p. 233.
Age-Dependent Changes in (Na, K)-ATPase Activity in Brains of Mice Susceptible to Seizures M i c e of t h e D B A s t r a i n , s u s c e p t i b l e t o a t I d i o g e n i c s e i z u r e s , h a v e c o n v u l s i o n s a t t h e a g e of 30 d a y s w h e n t h e y a r e e x p o s e d t o h e a t , w h e r e a s m i c e of t h e C57 s t r a i n d o n o t 1. S i n c e D B A m i c e d o n o t h a v e c o n v u l s i o n s w i t h e l e v a t e d t e m p e r a t u r e a t 20 or a t 40 d a y s , t h e y s e e m t o b e a m o d e l of f e b r i l e c o n v u l s i o n s i n h u m a n s 1, a n d i n t e r e s t attaches to features that distinguish them from the s e i z u r e - r e s i s t a n t C57 s t r a i n . C u r i o u s l y e n o u g h t h e f i n d i n g s of ABOOD a n d GERARD ~ h a v e n e v e r b e e n c o n f i r m e d t h a t b r a i n s of D B A m i c e h a v e l o w e r A T P a s e a n d a l o w e r P / O r a t i o t h a n t h o s e of C57 m i c e a t t h e a g e of s e i z u r e s u s c e p t i b i l i t y b u t n o t b e f o r e or a f t e r . T h e a u t h o r s c o u l d n o t t h e n d i f f e r e n t i a t e t h e f o r m of A T P a s e ; it is n o w
k n o w n - - t h a t A T P a s e a c t i v i t y i n b r a i n is l a r g e l y i n t h e f o r m a c t i v a t e d ~by N a + a n d 1K+, i.e. (Na, K ) - A T P a s e a. For this reason I studied ATPase activity in microsomal m e m b r a n e s of b r a i n s of DTBA m i c e a t t h e a g e o f s u s c e p t i b i l i t y ; 30 d a y s ; a n d b e f o r e a n d a f t e r , a t 20 a n d 60 days. The results were compared with those of non1 L. HERTZ, A. SCHOUSBOE, B. FORMBY and M. LENNoz-BUCHTHAL, Epilepsia 75, 619 (1974). s L. G. ABOOD and R. W. GERARD, in Biochemistry o] the Developing Nervous System (Ed. H. WAELSCH; Academic Press, New York 1955). J. C. SKOU, Biochim. biophys. Acta 58, 314 (1962).
