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Effects of opioid drugs on dopamine mediated locomotor activity in rats

Thesis/Dissertation:

Abstract

Opioid drugs influence various behavioural parameters including locomotor activity in experimental animals. The interaction between the opioid and dopaminergic systems is one possible explanation for the effect of opioid drugs on locomotor activity. In this study behavioural and biochemical assays were done to investigate the interaction between the opioid and dopaminergic systems. Behavioural studies were done by measurement of locomotor activity (LA) of rats after acute or chronic pretreatment with opioid andor dopaminergic drugs. Biochemical studies were in the form of radioligand binding assays, the effect on the number (Bmax) and affinity (K/sub D/) of receptors was measured after chronic pretreatment with opioid andor dopaminergic drugs. The opioid drugs used are morphine, nalbuphine and naloxone. Dopaminergic drugs used included: agonists-apomorphine and piribedil; antagonists-pimozide, haloperidol, chlorpromazine. In the acute situation increased LA was obtained with morphine and the DA agonists. A correlation between the behavioural and biochemical assays was found. Chronic pretreatment with morphine enhanced apomorphine induced LA, this supersensitivity was also measured as an increased receptor density (Bmax) of D2 receptors in the striatum. Chronic morphine pretreatment caused a decrease in morphine induced LA, while this subsensitivity was not apparent in the ligand binding assays - where no change in  More>>
Authors:
Publication Date:
Jan 01, 1986
Product Type:
Thesis/Dissertation
Reference Number:
AIX-19-054917; EDB-88-116606
Resource Relation:
Other Information: Thesis (M.Sc.)
Subject:
59 BASIC BIOLOGICAL SCIENCES; DOPAMINE; RECEPTORS; MORPHINE; BIOLOGICAL EFFECTS; BIOCHEMICAL REACTION KINETICS; ACUTE EXPOSURE; BRAIN; CEREBRUM; CHRONIC EXPOSURE; ENDORPHINS; ENZYME IMMUNOASSAY; HOMOGENATES; LABELLING; LIGANDS; RATS; SENSITIVITY; SYMPATHOLYTICS; SYMPATHOMIMETICS; TRITIUM COMPOUNDS; ALKALOIDS; AMINES; ANALGESICS; ANIMALS; AROMATICS; AUTONOMIC NERVOUS SYSTEM AGENTS; BODY; CARDIOTONICS; CARDIOVASCULAR AGENTS; CENTRAL NERVOUS SYSTEM; CENTRAL NERVOUS SYSTEM DEPRESSANTS; DRUGS; HYDROXY COMPOUNDS; IMMUNOASSAY; KINETICS; LABELLED COMPOUNDS; MAMMALS; MEMBRANE PROTEINS; NARCOTICS; NERVOUS SYSTEM; NEUROREGULATORS; OPIUM; ORGANIC COMPOUNDS; ORGANS; PHENOLS; POLYPHENOLS; PROTEINS; REACTION KINETICS; RODENTS; VERTEBRATES; 550501* - Metabolism- Tracer Techniques; 550101 - Behavioral Biology- Tracer Techniques
OSTI ID:
7143091
Research Organizations:
Potchefstroom Univ. for C.H.E. (South Africa)
Country of Origin:
South Africa
Language:
English
Availability:
Registrar, Potchefstroom University for CHE, Potchefstroom, 2520, South Africa.
Submitting Site:
INIS
Size:
Pages: 157
Announcement Date:

Thesis/Dissertation:

Citation Formats

Leathern, L L. Effects of opioid drugs on dopamine mediated locomotor activity in rats. South Africa: N. p., 1986. Web.
Leathern, L L. Effects of opioid drugs on dopamine mediated locomotor activity in rats. South Africa.
Leathern, L L. 1986. "Effects of opioid drugs on dopamine mediated locomotor activity in rats." South Africa.
@misc{etde_7143091,
title = {Effects of opioid drugs on dopamine mediated locomotor activity in rats}
author = {Leathern, L L}
abstractNote = {Opioid drugs influence various behavioural parameters including locomotor activity in experimental animals. The interaction between the opioid and dopaminergic systems is one possible explanation for the effect of opioid drugs on locomotor activity. In this study behavioural and biochemical assays were done to investigate the interaction between the opioid and dopaminergic systems. Behavioural studies were done by measurement of locomotor activity (LA) of rats after acute or chronic pretreatment with opioid andor dopaminergic drugs. Biochemical studies were in the form of radioligand binding assays, the effect on the number (Bmax) and affinity (K/sub D/) of receptors was measured after chronic pretreatment with opioid andor dopaminergic drugs. The opioid drugs used are morphine, nalbuphine and naloxone. Dopaminergic drugs used included: agonists-apomorphine and piribedil; antagonists-pimozide, haloperidol, chlorpromazine. In the acute situation increased LA was obtained with morphine and the DA agonists. A correlation between the behavioural and biochemical assays was found. Chronic pretreatment with morphine enhanced apomorphine induced LA, this supersensitivity was also measured as an increased receptor density (Bmax) of D2 receptors in the striatum. Chronic morphine pretreatment caused a decrease in morphine induced LA, while this subsensitivity was not apparent in the ligand binding assays - where no change in receptor number was observed. Chronic naloxone pretreatment enhanced morphine induced LA, as well as increased the Bmax of opioid receptors in the whole brain. It is concluded that an interaction between the opioid and dopaminergic systems does exist, and may account for the mechanism of action of the opioids.}
place = {South Africa}
year = {1986}
month = {Jan}
}