Apomorphine-induced inhibition of neostriatal activity is enhanced by lesions induced by 6-hydroxydopamine but not by long-term administration of amphetamine

Kevin Alloway, G. V. Rebec

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Single-unit activity was recorded in the neostriatum of locally-anesthetized, immobilized rats which had received either a unilateral injection of 6-hydroxydopamine (6-OHDA) into the nigroneostriatal dopamine pathway, or repeated injections (twice daily for 6 days) of saline, 1.0, 5.0 or 10.0 mg kg (+)-amphetamine. A staircase regimen of apomorphine was administered intravenously to each rat to determine if the long-term administration of amphetamine changed the sensitivity of postsynaptic dopamine receptors in a way comparable to that produced by 6-hydroxydopamine. In all groups, the most frequent response to apomorphine was inhibition of neostriatal activity. In saline-treated rats, most units were moderately excited by small doses of apomorphine (0.0025-0.02 mg kg) and then inhibited by doses exceeding 0.04 mg kg. In rats with lesions induced by 6-hydroxydopamine, apomorphine caused significantly more inhibition than in saline-treated animals. By contrast, neuronal responses in amphetamine-treated rats were not significantly different from those of saline controls. These results indicate that the long-term administration of amphetamine produces an augmentation of behavior by some mechanism other than an increase in the sensitivity of postsynaptic dopamine receptors.

Original languageEnglish (US)
Pages (from-to)1033-1039
Number of pages7
JournalNeuropharmacology
Volume23
Issue number9
DOIs
StatePublished - Jan 1 1984

Fingerprint

Apomorphine
Oxidopamine
Amphetamine
Dopamine Receptors
Neostriatum
Injections
Dopamine
Inhibition (Psychology)

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Cellular and Molecular Neuroscience

Cite this

@article{e5216488a4204f2399c217433963ce56,
title = "Apomorphine-induced inhibition of neostriatal activity is enhanced by lesions induced by 6-hydroxydopamine but not by long-term administration of amphetamine",
abstract = "Single-unit activity was recorded in the neostriatum of locally-anesthetized, immobilized rats which had received either a unilateral injection of 6-hydroxydopamine (6-OHDA) into the nigroneostriatal dopamine pathway, or repeated injections (twice daily for 6 days) of saline, 1.0, 5.0 or 10.0 mg kg (+)-amphetamine. A staircase regimen of apomorphine was administered intravenously to each rat to determine if the long-term administration of amphetamine changed the sensitivity of postsynaptic dopamine receptors in a way comparable to that produced by 6-hydroxydopamine. In all groups, the most frequent response to apomorphine was inhibition of neostriatal activity. In saline-treated rats, most units were moderately excited by small doses of apomorphine (0.0025-0.02 mg kg) and then inhibited by doses exceeding 0.04 mg kg. In rats with lesions induced by 6-hydroxydopamine, apomorphine caused significantly more inhibition than in saline-treated animals. By contrast, neuronal responses in amphetamine-treated rats were not significantly different from those of saline controls. These results indicate that the long-term administration of amphetamine produces an augmentation of behavior by some mechanism other than an increase in the sensitivity of postsynaptic dopamine receptors.",
author = "Kevin Alloway and Rebec, {G. V.}",
year = "1984",
month = "1",
day = "1",
doi = "10.1016/0028-3908(84)90125-4",
language = "English (US)",
volume = "23",
pages = "1033--1039",
journal = "Neuropharmacology",
issn = "0028-3908",
publisher = "Elsevier Limited",
number = "9",

}

TY - JOUR

T1 - Apomorphine-induced inhibition of neostriatal activity is enhanced by lesions induced by 6-hydroxydopamine but not by long-term administration of amphetamine

AU - Alloway, Kevin

AU - Rebec, G. V.

PY - 1984/1/1

Y1 - 1984/1/1

N2 - Single-unit activity was recorded in the neostriatum of locally-anesthetized, immobilized rats which had received either a unilateral injection of 6-hydroxydopamine (6-OHDA) into the nigroneostriatal dopamine pathway, or repeated injections (twice daily for 6 days) of saline, 1.0, 5.0 or 10.0 mg kg (+)-amphetamine. A staircase regimen of apomorphine was administered intravenously to each rat to determine if the long-term administration of amphetamine changed the sensitivity of postsynaptic dopamine receptors in a way comparable to that produced by 6-hydroxydopamine. In all groups, the most frequent response to apomorphine was inhibition of neostriatal activity. In saline-treated rats, most units were moderately excited by small doses of apomorphine (0.0025-0.02 mg kg) and then inhibited by doses exceeding 0.04 mg kg. In rats with lesions induced by 6-hydroxydopamine, apomorphine caused significantly more inhibition than in saline-treated animals. By contrast, neuronal responses in amphetamine-treated rats were not significantly different from those of saline controls. These results indicate that the long-term administration of amphetamine produces an augmentation of behavior by some mechanism other than an increase in the sensitivity of postsynaptic dopamine receptors.

AB - Single-unit activity was recorded in the neostriatum of locally-anesthetized, immobilized rats which had received either a unilateral injection of 6-hydroxydopamine (6-OHDA) into the nigroneostriatal dopamine pathway, or repeated injections (twice daily for 6 days) of saline, 1.0, 5.0 or 10.0 mg kg (+)-amphetamine. A staircase regimen of apomorphine was administered intravenously to each rat to determine if the long-term administration of amphetamine changed the sensitivity of postsynaptic dopamine receptors in a way comparable to that produced by 6-hydroxydopamine. In all groups, the most frequent response to apomorphine was inhibition of neostriatal activity. In saline-treated rats, most units were moderately excited by small doses of apomorphine (0.0025-0.02 mg kg) and then inhibited by doses exceeding 0.04 mg kg. In rats with lesions induced by 6-hydroxydopamine, apomorphine caused significantly more inhibition than in saline-treated animals. By contrast, neuronal responses in amphetamine-treated rats were not significantly different from those of saline controls. These results indicate that the long-term administration of amphetamine produces an augmentation of behavior by some mechanism other than an increase in the sensitivity of postsynaptic dopamine receptors.

UR - http://www.scopus.com/inward/record.url?scp=0021130599&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021130599&partnerID=8YFLogxK

U2 - 10.1016/0028-3908(84)90125-4

DO - 10.1016/0028-3908(84)90125-4

M3 - Article

C2 - 6096755

AN - SCOPUS:0021130599

VL - 23

SP - 1033

EP - 1039

JO - Neuropharmacology

JF - Neuropharmacology

SN - 0028-3908

IS - 9

ER -