THE EFFECT OF BROMOCRIPTINE ON RAT STRIATAL ADENYLATE CYCLASE AND RAT BRAIN MONOAMINE METABOLISM R. MARKSTEIN' and P. L. HERRLING Biological and Medical Research. Sandoz Ltd.. 4002 Basel. Switzerland and
H. R. BCRKI. H. A s P t R and W. RUCH Research Institute Wander. Sandoz Research Unit. 3000 Berne. Saitmland ( R c c r i w d 8 Drccwher 1977. R c ~ s c t l4 April 1978. .4 CORRODI & HAUsou (1966). H44 68 (250 nig kg i.p.) aas administered 15 min after the test drugs. the rats were killed 2 h later and the DA content in the striaturn dctermined. NA u a s determined fluorinietricallq in the pooled brain stems of 2 rats after adsorption from neutralized pcrchloric acid extracts on aluminum oside (WI-IL-MALHI.RHI.1971). and elution nith dilute perchloric acid (ALTON & SAYRF. 1962). with a contin~iousflow analqser a s described by Z [ SPAS & CCK)[.I\(1969). The tiirno\cr rate of NA w a s assessed after blockade of DA-/l-hqdroxqlase with DDC. as described hy C A Kssos I vt li/. (19661. D D C (500 mg kg 5.c.) was administered 15 min after the drugs. the rats were killed 2 h later and the NA content in the brain stem determined. For the determination of D O P A C and M O P E G .SO, the tissties were homogcnized in 0.4 u-perchloric acid and the homogenates were centrifuged at l2.8OO.y for 10inin at ( b 4 C. The supernatant was used for analysis. D O P A C a a s extracted from the perchloric acid supernatants of thc poolcd striata or limbic sjstems o f 2 rats with ii-hut>I acetate and re-extracted from the wbut)l acctate phasc with ethjlenc-diaminc solution for fluorimetric determination according to the method of SPANO& N I - t ~(1971). M O P E G S O , was isolltted from the neutralized perchloric acid supernatants of 2 rats bq adsorption onto DOWEX I x 4 10@20Omesh (C'I-form. column 4.5 x 0.5cm) eluted hith diluted pcrchloric acid and determined tluorimetricallq according to the method of M r . 1 ~& NtFi (1972). For the determination of 5-HT and 5-HIAA. the pooled uhole brains or cerebral cortices of 2 rats were homogenized in 0.1 x-hqdrochloric acid containing 0.5",, ascorbic acid and the proteins precipitated by addition of zinc sulphnte and sodicim hydroxide. The reaction mixtures were filtered to )ield a clear solution which was used for the determinations. 5-HIAA &as extracted from this solution ;it p H 1-2 with 11-butyl acetate and re-extracted from the ii-but>l iicctate phase at p H 7 with phosphate buffer 0.1 M. 5-HT w a s extracted at p H 10 with 11-butanol and re-extracted from the butanol with diluted hydrochloric acid. 5-HT and 5-HIAA were determined Huorimetricallq in the hqdrochloric acid and phosphate buffer solutions respecti\el!. suficient hqdrochloric acid being added in each case to give 3 u solutions (GIKALout & V A L ~ I I . L I1969). . The turno\er of 5-HT was assessed after blockade of trqptophan hldrox) lase with 6-FTP (PLTIRS.1971). 6-FTP (250mg,kg i.p.) was administered 15 min after the drugs. and the animals were killed 2 h later and the 5-HT content determined. Results of the biochemical determinations were corrected for recoveries of internal standards added to the tissue samples. Recoveries (Mean & s.D.) of the various metabolites were: 75 & ?.I",, DA ( n = 35). 85 5.4",, DOPAC ( n = 115),
ti/.
84 i 2.6",, NA (11 = 44). 90 & @ I , , M O P E G . SO, In = 36). 63.9 2 4.l"
H. R. BCRKI. H. A s P t R and W. RUCH Research Institute Wander. Sandoz Research Unit. 3000 Berne. Saitmland ( R c c r i w d 8 Drccwher 1977. R c ~ s c t l4 April 1978. .4 CORRODI & HAUsou (1966). H44 68 (250 nig kg i.p.) aas administered 15 min after the test drugs. the rats were killed 2 h later and the DA content in the striaturn dctermined. NA u a s determined fluorinietricallq in the pooled brain stems of 2 rats after adsorption from neutralized pcrchloric acid extracts on aluminum oside (WI-IL-MALHI.RHI.1971). and elution nith dilute perchloric acid (ALTON & SAYRF. 1962). with a contin~iousflow analqser a s described by Z [ SPAS & CCK)[.I\(1969). The tiirno\cr rate of NA w a s assessed after blockade of DA-/l-hqdroxqlase with DDC. as described hy C A Kssos I vt li/. (19661. D D C (500 mg kg 5.c.) was administered 15 min after the drugs. the rats were killed 2 h later and the NA content in the brain stem determined. For the determination of D O P A C and M O P E G .SO, the tissties were homogcnized in 0.4 u-perchloric acid and the homogenates were centrifuged at l2.8OO.y for 10inin at ( b 4 C. The supernatant was used for analysis. D O P A C a a s extracted from the perchloric acid supernatants of thc poolcd striata or limbic sjstems o f 2 rats with ii-hut>I acetate and re-extracted from the wbut)l acctate phasc with ethjlenc-diaminc solution for fluorimetric determination according to the method of SPANO& N I - t ~(1971). M O P E G S O , was isolltted from the neutralized perchloric acid supernatants of 2 rats bq adsorption onto DOWEX I x 4 10@20Omesh (C'I-form. column 4.5 x 0.5cm) eluted hith diluted pcrchloric acid and determined tluorimetricallq according to the method of M r . 1 ~& NtFi (1972). For the determination of 5-HT and 5-HIAA. the pooled uhole brains or cerebral cortices of 2 rats were homogenized in 0.1 x-hqdrochloric acid containing 0.5",, ascorbic acid and the proteins precipitated by addition of zinc sulphnte and sodicim hydroxide. The reaction mixtures were filtered to )ield a clear solution which was used for the determinations. 5-HIAA &as extracted from this solution ;it p H 1-2 with 11-butyl acetate and re-extracted from the ii-but>l iicctate phase at p H 7 with phosphate buffer 0.1 M. 5-HT w a s extracted at p H 10 with 11-butanol and re-extracted from the butanol with diluted hydrochloric acid. 5-HT and 5-HIAA were determined Huorimetricallq in the hqdrochloric acid and phosphate buffer solutions respecti\el!. suficient hqdrochloric acid being added in each case to give 3 u solutions (GIKALout & V A L ~ I I . L I1969). . The turno\er of 5-HT was assessed after blockade of trqptophan hldrox) lase with 6-FTP (PLTIRS.1971). 6-FTP (250mg,kg i.p.) was administered 15 min after the drugs. and the animals were killed 2 h later and the 5-HT content determined. Results of the biochemical determinations were corrected for recoveries of internal standards added to the tissue samples. Recoveries (Mean & s.D.) of the various metabolites were: 75 & ?.I",, DA ( n = 35). 85 5.4",, DOPAC ( n = 115),
ti/.
84 i 2.6",, NA (11 = 44). 90 & @ I , , M O P E G . SO, In = 36). 63.9 2 4.l"
