Centrally acting histamine H1 antagonists promote the development of amygdala kindling in rats.

We studied the effect of histamine H1 antagonists on the development of amygdala kindling, an experimental model of epilepsy, in rats. The centrally acting histamine H1 antagonists including pyrilamine (mepyramine) and ketotifen showed an acceleration in the rate of electrical stimulation to develop fully kindled convulsive seizures. On the contrary, epinastine, a histamine H1 antagonist which scarcely enters the brain, showed no acceleration. These findings suggest that the central histaminergic neuron system plays an inhibitory role on the seizure development through central histamine H1 receptors.