Studies on the pharmacology of neurones in the nucleus accumbens of the rat
Studies on the pharmacology of neurones in the nucleus accumbens of the rat
A study was made of the pharmacology of neurones in the nucleus accumbena of the rat. Experiments were performed on urethane anaesthetised female albino Wistar rats and involved the microiontophoretic application of drugs, their agonists and antagonists. Single extracellular recordings were made of neuronal responses via 6-barrelled 'parallel' microelectrodes. In most cases, dl-homocysteic acid was used to drive the cells.For the sake of comparison, experiments were also performed in the caudate nucleus and cerebellum.A limited number of experiments into the functioning of the nucleus accumbena were also made involving electrical stimulation of the AlO dopamine containing cell bodies. Experiments involving the microinjection of drugs into the nucleus accumbens of conscious rats were also undertaken. Neurones in the nucleus accumbens were inhibited by a wide variety of compounds including dopamine, adenosine3',5'-cyclic monophosphate (cyclic AMP), 2-amino-6,7-dihydroxy-l,2,3,4-tetrahydronaphthalene (AUTN), apomorphine, ergometrine, amphetamine, 5-hydroxytryptamine (51sT), d-lysergic acid diethylamide (LSD) and morphine. Neurotensin, substance 1' and methionine- and leucine-enkephalin were also found to he inhibitory. Angiotensin was, however, without effect. The amino acids aspartate and glutamate were foundto be excitatory, whilst 3-aminobutyric acid, glycine, taurine and serine wore found to depress neuronal activity. The responses of glycino and 11-aminobutyric acid were antagonised by strychnine and picrotoxin respectively.Acetylcholine and dl-homocysteic acid caused excitation of nucleus accumbens neurones; the effects of acetylcholine were blocked by atropine. The responses to both dopamine and 5-11T were antagonised by oc-flupenthixol. Naloxone blocked the depressant effects of morphine and enkephalin. The results are consistent with the suggestion that dopamine is and inhibitory transmitter in the nucleus accumbens and support the hypothesis that the effects of dopamine are mediated by cyclic AMP. The locomotor stimulants, A3)TN, amphetamine and ergometrine mimicked the actions of dopamine in this brain region. These results support the suggestion that dopamine receptors in the nucleus accumbens are involved in the actions of locomotor stimulant drugs.
University of Southampton
1977
McCarthy, Paul Stephen
(1977)
Studies on the pharmacology of neurones in the nucleus accumbens of the rat.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
A study was made of the pharmacology of neurones in the nucleus accumbena of the rat. Experiments were performed on urethane anaesthetised female albino Wistar rats and involved the microiontophoretic application of drugs, their agonists and antagonists. Single extracellular recordings were made of neuronal responses via 6-barrelled 'parallel' microelectrodes. In most cases, dl-homocysteic acid was used to drive the cells.For the sake of comparison, experiments were also performed in the caudate nucleus and cerebellum.A limited number of experiments into the functioning of the nucleus accumbena were also made involving electrical stimulation of the AlO dopamine containing cell bodies. Experiments involving the microinjection of drugs into the nucleus accumbens of conscious rats were also undertaken. Neurones in the nucleus accumbens were inhibited by a wide variety of compounds including dopamine, adenosine3',5'-cyclic monophosphate (cyclic AMP), 2-amino-6,7-dihydroxy-l,2,3,4-tetrahydronaphthalene (AUTN), apomorphine, ergometrine, amphetamine, 5-hydroxytryptamine (51sT), d-lysergic acid diethylamide (LSD) and morphine. Neurotensin, substance 1' and methionine- and leucine-enkephalin were also found to he inhibitory. Angiotensin was, however, without effect. The amino acids aspartate and glutamate were foundto be excitatory, whilst 3-aminobutyric acid, glycine, taurine and serine wore found to depress neuronal activity. The responses of glycino and 11-aminobutyric acid were antagonised by strychnine and picrotoxin respectively.Acetylcholine and dl-homocysteic acid caused excitation of nucleus accumbens neurones; the effects of acetylcholine were blocked by atropine. The responses to both dopamine and 5-11T were antagonised by oc-flupenthixol. Naloxone blocked the depressant effects of morphine and enkephalin. The results are consistent with the suggestion that dopamine is and inhibitory transmitter in the nucleus accumbens and support the hypothesis that the effects of dopamine are mediated by cyclic AMP. The locomotor stimulants, A3)TN, amphetamine and ergometrine mimicked the actions of dopamine in this brain region. These results support the suggestion that dopamine receptors in the nucleus accumbens are involved in the actions of locomotor stimulant drugs.
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Published date: 1977
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Local EPrints ID: 467248
URI: http://eprints.soton.ac.uk/id/eprint/467248
PURE UUID: bc449167-ff23-4b3a-91ab-76c7f17ff815
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Date deposited: 05 Jul 2022 08:16
Last modified: 05 Jul 2022 08:16
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Author:
Paul Stephen McCarthy
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