Lateral difference in responsiveness of norepinephrine-sensitive cyclic AMP-generating systems of rat cerebral cortex with iron-induced epileptic activity.

Responsiveness of norepinephrine-sensitive cyclic AMP-generating systems was examined in slices of different cortical areas of rats showing electrographic spike and wave complexes after unilateral injection of ferrous chloride solution into the sensorimotor cortex. Accumulation of cyclic AMP elicited by norepinephrine was greater on the injection side of the cortex than on the other. Similar lateral differences were detected in cyclic AMP levels antagonized by phentolamine or propranolol, in which 8-phenyltheophylline almost completely inhibited the elicitation of cyclic AMP accumulation by a norepinephrine-propranolol combination but not by a norepinephrine-phentolamine combination. These results suggest that alterations in cyclic AMP generation through the beta-adrenoceptor-coupled adenylate cyclase system and through alpha-adrenergic activation of the adenosine receptor-coupled adenylate cyclase system are closely related to the electrographic activity of iron-induced epilepsy.