Effect of L-prolyl-L-leucyl-glycinamide (PLG) on neuroleptic-induced catalepsy and dopamine/neuroleptic receptor bindings.

Abstract

The mechanism of action subserving the potential anti-Parkinsonian properties of L-prolyl-L-leucyl-glycinamide (PLG) was investigated in behavioural and neurochemical models of dopaminergic function in the rat. Acute administration of PLG (20 and 40 mg kg-1 SC) failed to alter appreciably the intensity of the cataleptic response elicited by haloperidol (3 mg kg-1 IP). By contrast, chronic PLG treatment (20, 40 and 80 mg kg-1 SC twice daily for five days) significantly attenuated haloperidol-induced catalepsy. The effect of PLG on in vitro dopamine/neuroleptic receptor binding in rat striatum as differentially labelled by apomorphine and spiroperidol was also examined. PLG selectively enhanced the affinity of the specific binding of agonist [3H] apomorphine to dopamine receptors in the striatum, but had no effect on [3H] spiroperidol binding. The behavioural and biochemical results obtained in the present study raise the possibility that PLG may facilitate nigro-striatal dopaminergic neurotransmission through interacting with a unique PLG receptor functionally coupled to the dopamine receptor-adenylate cyclase complex.

• Authors: S Chiu, C S Paulose, R K Mishra
• Journal: Peptides (Peptides) Vol. 2 Issue 1 Pg. 105-11 ( 1981) ISSN: 0196-9781 [Print] United States
• PMID: 6113579 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Receptors, Dopamine
• Receptors, Opioid
• Spiperone
• MSH Release-Inhibiting Hormone
• Haloperidol
• Apomorphine

Topics

• Animals
• Apomorphine (metabolism)
• Catalepsy (chemically induced, physiopathology)
• Dose-Response Relationship, Drug
• Haloperidol
• Humans
• Kinetics
• MSH Release-Inhibiting Hormone (pharmacology)
• Male
• Rats
• Receptors, Dopamine (drug effects, metabolism)
• Receptors, Opioid (drug effects, metabolism)
• Spiperone (metabolism)