Lack of substantial effect of the H(3)-antagonist thioperamide and of the non-selective mixed H(3)-antagonist/H(1)-agonist betahistine on amygdaloid kindled seizures.
We investigated whether some histamine H(3)-antagonists would attenuate amygdaloid kindled seizures in rats. Thioperamide, a standard H(3)-antagonist, did not significantly reduce either seizure ranks or afterdischarge duration (ADD). Betahistine which has both H(3)-antagonistic activity and H(1)-agonistic activity significantly reduced ADD, albeit mild at a toxic dose, though seizure ranks were not affected. In addition, L-histidine, the precursor of histamine, affected neither seizure ranks, nor ADD. It was shown that H(3)-antagonists have no significant inhibitory action against amygdaloid kindled seizures, probably because released histamine was unable to inhibit those seizures.
Yoshida
M
M
Department of Neurology, Division for the Visually Impaired, Tsukuba College of Technology, Kasuga 4-12-7, City of Tsukuba, 305, Ibaraki, Japan.
Noguchi
E
E
Tsuru
N
N
D000679:Amygdala / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001621:Betahistine / Q000494:pharmacology* / Q000627:therapeutic use; D017442:Histamine Agonists / Q000494:pharmacology* / Q000627:therapeutic use; D006633:Histamine Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D007696:Kindling, Neurologic / Q000187:drug effects* / Q000502:physiology; D008297:Male; D010880:Piperidines / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000188:drug therapy
D017442:Histamine Agonists; D006633:Histamine Antagonists; D010880:Piperidines; C052075:thioperamide; D001621:Betahistine