The study was designed to compare the proconvulsive activity of two
theophylline-containing bronchodilating agents,
aminophylline and
acepifylline and their antagonistic effects to
diazepam,
phenytoin,
MK-801 and
carbamazepine in electroshock seizure model in rats. Graded intensity (30-150 mA for 0.2 s) of electroshock was applied to different groups of rats pretreated either with
normal saline (0.5 ml, i.p.), graded doses (25-150 mgkg-1, i.p.) of
aminophylline, graded doses (70-560 mgkg-1, i.p.) of
acepifylline, graded doses of the antiseizure drugs or to rats pretreated with
aminophylline (25 mgkg-1, i.p.) + antiseizure drugs or
acepifylline (70 mgkg-1, i.p.) + antiseizure drugs. CI 50 +/- s.e.m. value was 88.41 +/- 2.14 mA in saline treated rats. In
aminophylline pretreated rats the values were 84.14 +/- 2.03, 68.06 +/- 1.24, 54.28 +/- 1.96 and 39.58 +/- 2.31 mA at 25 mgkg-1 (0.06 mmolekg-1), 50 mgkg-1 (0.12 mmolekg-1), 100 mgkg-1 (0.24 mmolekg-1) and 150 mgkg-1 (0.36 mmolekg-1), i.p. doses respectively. The values were 85.73 +/- 1.09, 64.86 +/- 2.37, 61.58 +/- 1.37 and 60.62 +/- 2.41 mA at 70 mgkg-1 (0.125 mmolekg-1), 140 mgkg-1 (0.25 mmolekg-1), 280 mgkg-1 (0.50 mmolekg-1) and 560 mgkg-1 (1.0 mmolekg-1), i.p. doses respectively for the
acepifylline pretreated groups of rats.
Diazepam,
MK-801,
phenytoin and
carbamazepine significantly antagonized electroshock-induced seizure in a dose-dependent manner. Subsensitizing dose of
aminophylline (25 mgkg-1, i.p.) but not that of
acepifylline (70 mgkg-1, i.p.) pretreatment significantly antagonized the efficacy of all the antiseizure drugs. The study highlighted that
acepifylline might be safely used in epileptic patients well controlled on
antiepileptic drugs.
Aminophylline, on the other hand, should be avoided since it might produce breakthrough seizure attacks due to its greater proconvulsive and anti-antiseizure
drug effects.