Norepinephrine-sensitive adenylate cyclase in rat hypothalamus: effects of adrenergic blockers and narcotics.

The norepinephrine-sensitive adenylate cyclase system in the rat brain was examined. Adrenergic blocking agents and the relative activity of structurally related catecholamines were employed to determine whether norepinephrine-stimulated accumulation of [3H]c-AMP in the hypothalamus occurred via alpha or beta adrenergic receptors. The results indicate that norepinephrine probably acts through a mixture of alpha and beta receptors in that both alpha and beta adrenergic blockers inhibited norepinephrine-induced accumulation of [3H]c-AMP. Morphine and levorphanol had no significant effect on adenylate cyclase or phosphodiesterase activities in hypothalamic slices or homogenates of several brain regions.