858-860Methionine-sulfoximine
(MSO), a convulsant is known to
increase
the activity of histamine N-methyl transferase. The effect of a selective H3
receptor agonist R- ( ) methylhistamine (RAMH) and antagonist (thioperamide,
THP) and some
antiepileptic
drugs (gabapentin and sodium valproate) have been evaluated on MSO-induced
convulsions in mice. The effect of THP was also evaluated in combination with
these antiepileptic drugs. Sodium valproate (300 mg/kg, po) and gabapentin
(400
mg/kg, po) offered protection against MSO-induced convulsions as evidenced by a
significant prolongation of latency to abnormal dorsoflexion and complete
protection against mortality within 6 h of administration. THP (15 mg/kg, ip)
alone and in combination with sub-effective doses of gabapentin (75 mg/kg, po)
and sodium valproate (75 mg/kg, po) revealed no significant differences from
the control group or either drug alone. Hence,
the
convulsant action of MSO does not appear to be mediated
via
histaminergic mechanisms