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ROLE OF CENTRAL β‐ADRENOCEPTORS IN THE CONTROL OF PENTYLENETETRAZOL‐INDUCED CONVULSIONS IN RATS
Author(s) -
LOUIS W.J.,
PAPANICOLAOU JENNY,
SUMMERS R.J.,
VAJDA F.J.E.
Publication year - 1982
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1982.tb09159.x
Subject(s) - pentylenetetrazol , medicine , epilepsy , anesthesia , pharmacology , neuroscience , anticonvulsant , biology
1 The role of central β‐adrenoceptors in the anticonvulsant effect of β‐adrenoceptor antagonists has been examined. 2 Oral administration of (−)‐and (+)‐propranolol (0.05–1 mg/kg) and (±)‐pindolol (0.025–0.5 mg/kg) produced a dose‐dependent decrease in duration of convulsions produced by pentylenetetrazol (PTZ 50 mg/kg, i.p.) in rats. 3 At the EC 5+ level, (−)‐propranolol is seven times more effective than the (+)‐isomer. 4 Oral administration of (−)‐, (+)‐or (±)‐practolol (1–10 mg/kg) or (−)‐or (+)‐timolol (1–10 mg/kg), two β‐adrenoceptor antagonists that do not penetrate the blood brain barrier, had no significant effect on the duration of PTZ‐induced convulsions. 5 Intracerebroventricular administration of (−)‐propranolol (0.5 μg/kg) or (−)‐timolol (0.25 μg/kg) produced highly significant anticonvulsant effects whereas the (+)‐isomers at the same dose level were ineffective. (±)‐Pindolol (0.25 μg/kg) was also much more effective given by this route than when given orally. The (+)‐and (−)‐isomers of the β 1 ‐adrenoceptor selective antagonist practolol (10 μg/kg) exerted only weak anticonvulsant effects. 6 This study provides evidence that β‐adrenoceptor antagonists exert an anticonvulsant effect through central β 2 ‐adrenoceptors. At high dose levels, additional anticonvulsant activity is associated with membrane stabilization in those antagonists which possess this property.