Mechanism of lithium action on the adrenergic function.

The intravenous injection of Lithium chloride (LiCl) in two dose levels (25 & 50 mg/kg) has led to a significant potentiation of the pressor response of rabbits to the i.v administration of both epinephrine and norepinephrine. The i.v injection of LiCl (50 mg/kg) resulted in a marked depression of the carotid occlusion reflex in rabbits. In vitro experiments revealed that LiCl (1.6 mcg/ml) and guanethidine (0.8 mcg/ml) exert the same action on the rabbit mesenteric nerve-intestine preparation and abolish the intestinal relaxation induced by electrical stimulation of the mesenteric nerve. Results confirm the assumption that Li might display a pre-synaptic, guanethidine-like, adrenergic neuronal blocking activity.