Clonidine modulates dopamine cell firing in rat ventral tegmental area

doi:10.1016/0014-2999(89)90765-6

European Journal of Pharmacology

Volume 165, Issue 1, 8 June 1989, Pages 11-18

https://doi.org/10.1016/0014-2999(89)90765-6 Get rights and content

Abstract

The effect of clonidine (5–20 μg/kg i.v.) on the activity of single, identified dopamine neurons in the ventral tegmental area of the mesencephalon was studied in chloral hydrate-anesthetized male rats. Clonidine regularized cell firing without affecting the firing rate of the neurons. This effect was blocked by idazoxan (0.5 mg/kg i.v.) or yohimbine (1.0 mg/kg i.v.), but not by phentolamine (1.0 mg/kg i.v.), indicating that clonidine acts at central α₂-adrenoceptors. Idazoxan or yohimbine alone produced deregularization and excitation of cell firing. Pretreatment with reserpine (5 mg/kg s.c.) 4 h before the experiment abolished the neuromodulatory effect of clonidine. Thus, the regularization of ventral tegmental area dopamine cell firing by clonidine is indirect and dependent on endogenous monoamines in brain, and, in principle, a tonic adrenergic control of DA cell firing pattern is indicated. The regularization of DA cell activity produced by clonidine may underlie certain therapeutic neuropsychiatric actions of the drug.

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Citation Excerpt :
Similarly, NE and UK14304 activate a non-specific cationic conductance that produced a small inward current (Cathala et al., 2002). In conjunction, these two postsynaptic actions render DA neurons more excitable and might play a role in the transition to burst firing observed with systemic administration of α2 antagonists (Grenhoff and Svensson, 1988; Grenhoff and Svensson, 1989) These action of α2 adrenoceptors may also synergize with the postsynaptic activation of α1 adrenoceptors (Goertz et al., 2015). Presynaptic modulation by α2 adrenoceptors affects both inhibitory and excitatory inputs to DA neurons.
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This article is part of a Special Issue entitled SI: Noradrenergic System.

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Clonidine modulates dopamine cell firing in rat ventral tegmental area

Abstract

Life Sci.

European J. Pharmacol.

Neuropharmacology

Neuroscience

Life Sci.

Acta Physiol. Scand.

Neuroscience

European J. Pharmacol.

European J. Pharmacol.

Brain Res.

Brain Res. Bull.

Exp. Neurol.

Brain Res. Rev.

Biochem. Pharmacol.

Dopamine ‘autoreceptors’: pharmacological characterization by microiotophoretic single cell recording studies

Naunyn-Schmiedeb. Arch. Pharmacol.

Adrenergic receptor blocking agents: effects on central noradrenaline and dopamine receptors and on motor activity

Psychopharmacologia

Drugs which block the storage of 5-hydroxytryptamine and related amines

Evidence for the existence of monoamine-containing neurones in the central nervous system. I. Demonstration of monoamines in the cell bodies of brain system neurons

Acta Physiol. Scand.

Comparison of the α-adrenoceptor antagonist profiles of idazoxan (RX 781094), yohimbine, rauwolscine and corynanthine

Naunyn-Schmiedeb. Arch. Pharmacol.

Clonidine treatment of schizophrenia

Acta Psychiat. Scand.