NORADRENERGIC INFLUENCES ON SOUND-INDUCED SEIZURES

  • 1 January 1980
    • journal article
    • research article
    • Vol. 214  (2) , 437-442
Abstract
The preferential .alpha.-2 noradrenergic agonists, clonidine (0.2-0.4 mg/kg), oxymetazoline (2.5-10.0 mg/kg) and UK 14,304 [5-bromo-6-[2-imidazolin-2-ylimino]-quinoxaline] (0.6 mg/kg), when given i.p., reduce the severity of audiogenic seizures in 19- to 26-day-old DBA/2 mice. This protective effect can be diminished or reversed by .alpha.-2 noradrenergic antagonists, e.g., yohimbine (2.5 mg/kg) or piperoxan (20-50 mg/kg) given i.p. or phentolamine (100 .mu.g) given intracerebroventricularly (i.c.v.). It is not reversed by the preferential .alpha.-1 noradrenergic antagonist phenoxybenzamine (5 mg/kg) given i.p. Yohimbine, (1-2.5 mg/kg), piperoxan (20-50 mg/kg) or phenoxybenzamine (5 mg/kg) given i.p. alone did not change the severity of audiogenic seizure responses. Phentolamine (10-100 .mu.g) or prazosin (10-50 .mu.g) given i.c.v. induced spontaneous limb myoclonus in some mice. Audiogenic seizure responses were unchanged after phentolamine (10-100 .mu.g) but were reduced after prazosin (25-50 .mu.g). Activation of a receptor pharmacologically similar to the peripheral .alpha.-2 noradrenergic receptor protects against seizures in this epilepsy model.

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