Stimulation by nicotine of the spontaneous release of [3H]γ-aminobutyric acid in the substantia nigra and in the globus pallidus of the rat - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Brain Research Année : 1994

Stimulation by nicotine of the spontaneous release of [3H]γ-aminobutyric acid in the substantia nigra and in the globus pallidus of the rat

Résumé

The effect of (-)-nicotine on the spontaneous release of [3H]gamma-aminobutyric acid ([3H]GABA) was studied in vitro in rat substantia nigra (SN) and globus pallidus (GP) slices. In both structures, nicotine (10(-4) M) elicited a transient increase of [3H]GABA release lasting no more than 2.5 min. At the peak of the effect, a 18.5% and 25% increase of [3H]GABA was observed in GP and SN slices, respectively. At lower concentration (10(-5) M), nicotine produced a small but significant transient increase (+8%) in GP slices whereas this concentration was ineffective in SN slices. Pempidine (10(-5) M) totally antagonized the 10(-4) M nicotine-induced effect in SN and GP. The increase of [3H]GABA release elicited by 10(-4) M nicotine was abolished when Ca2+ concentration in the superfusion medium was lowered from 2.4 to 0.4 mM. To investigate a possible dopaminergic (DA) link in the response, we examined the sensitivity of the nicotine-induced effect to DA D1 (SCH23390) and D2 (sulpiride) receptor antagonists. In SN, SCH23390 (10(-6) M) abolished the 10(-4) M nicotine-induced effect. In GP, sulpiride (10(-5) M) failed to modify the response. Moreover, SCH23390 partially reversed the nicotine-induced effect (-37%) in GP. Taken together these results indicate that nicotine differentially modulate the [3H]GABA release in SN and GP. In SN, the nicotine-induced [3H]GABA release appears to be mediated by DA neurons. In GP, only a part of the nicotinic response involved a DA link. A possible direct stimulation of nicotinic receptors localized on striato-pallidal terminals is discussed.

Dates et versions

hal-03537831 , version 1 (20-01-2022)

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Citer

Nathalie Kayadjanian, Sylvie Rétaux, Annie Menétrey, Marie-Jo Besson. Stimulation by nicotine of the spontaneous release of [3H]γ-aminobutyric acid in the substantia nigra and in the globus pallidus of the rat. Brain Research, 1994, 649 (1-2), pp.129-135. ⟨10.1016/0006-8993(94)91056-1⟩. ⟨hal-03537831⟩
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