Behavioral effects of lithium on presynaptic sites of catecholaminergic neurons in the mouse

• Published in: Archives internationales de pharmacodynamie et de thérapie Vol. 282; no. 1; p. 58
• Main Authors: Ushijima, I, Yamada, K, Furukawa, T
• Format: Journal Article
• Language: English
• Published: Belgium 01-07-1986
• Subjects: Animals; Apomorphine - pharmacology; Catecholamines - physiology; Drug Interactions; Haloperidol - pharmacology; Lithium - pharmacology; Male; Methamphetamine - pharmacology; Mice; Motor Activity - drug effects; Neurons - physiology; Synapses - drug effects; Tetrabenazine - pharmacology; Thyrotropin-Releasing Hormone - pharmacology
• ISSN: 0003-9780

The effect of lithium on locomotor activity in mice was studied and an attempt was made to elucidate the neuronal mechanisms involved. Lithium chloride (200 mg/kg, i.p.) administered acutely or daily for 7 days did not affect locomotor activity. A single injection of apomorphine at a low dose of 0.25 mg/kg (i.p.) markedly decreased locomotor activity but repeated injection of the drug produced hyperlocomotion accompanied by sniffing. Methamphetamine (1 mg/kg, i.p.), haloperidol (0.02 mg/kg, i.p.), thyrotropin releasing hormone (5 mg/kg, i.p.) or apomorphine (1 mg/kg, i.p.) exerted a biphasic action in locomotor activity, i.e. an initial increase and subsequent decrease. This initial hyperlocomotion induced by these drugs, except for apomorphine, was inhibited by lithium (200 mg/kg, i.p. X 1) or a low dose of apomorphine (0.25 mg/kg, i.p. X 1). The subsequent hypolocomotion was also attenuated by lithium, but not by apomorphine. Imipramine (10 mg/kg, i.p.) increased the hyperlocomotion induced by methamphetamine. The inhibitory effect of tetrabenazine (5 mg/kg, i.p.) on locomotor activity was attenuated after repeated treatment with lithium (200 mg/kg, i.p. X 7) or imipramine (10 mg/kg, i.p. X 7). The results suggest that lithium may inhibit dopaminergic neuron activities, probably not through an activation of presynaptic dopamine autoreceptors.