Neurotensin counteracts apomorphine-induced inhibition of dopamine release as studied by microdialysis in rat neostriatum

doi:10.1016/0006-8993(89)90627-6

Brain Research

Volume 502, Issue 2, 20 November 1989, Pages 319-324

https://doi.org/10.1016/0006-8993(89)90627-6 Get rights and content

Abstract

Microdialysis in the neostriatum of the halothane-anesthetized male rats was used to study the effect of neurotensin on the release of dopamine and its metabolites in the absence or presence of systemic apomorphine treatment. Perfusate levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were assayed by high-performance liquid chromatography in combination with electrochemical detection. Perfusion with neurotensin (1000 nM but not 10 nM) increased the dialysate levels of dopamine without affecting those of DOPAC and HVA. Systemic treatment with apormophine (0.05 and 0.5 mg/kg, s.c.) reduced the dialysate levels of dopamine, DOPAC and HVA in a dose-related way. Neurotensin (10 nM but not 1 nM) counteracted the inhibitory effect of apomorphine on dialysate levels of dopamine without affecting those of DOPAC and HVA. The results indicate a facilitatory effect of neurotensin on dopamine release in rat neostriatum. It is suggested that activation of neurotensin receptors ay cause a reduction in the affinity of dopamine autoreceptors, since the low dose of neurotensin is able to counteract the inhibitory effect of apomorphine on dopamine release.

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Neurotensin counteracts apomorphine-induced inhibition of dopamine release as studied by microdialysis in rat neostriatum

Abstract

J. Biol. Chem.

Neurochem. Int.

Brain Research

Neuroscience

Psychoneuroendocrinology

Eur. J. Pharmacol.

Brain Research

Peptides

Brain Research

Neurochem. Int.

Neuropeptides

Eur. J. Pharmacol.

Eur. J. Pharmacol.

Neurotensin in vitro markedly reduces the affinity in subcortical limbic [3H]N-propylnorapomorphine binding sites

Acta Physiol. Scand.

Neurotensin in vitro markedly reduces the affinity in subcortical limbic [³H]N-propylnorapomorphine binding sites