Pallidal substrate of morphine-induced locomotion.
Bilateral microinjections of morphine hydrochloride (5.0; 7.5; 10.0 micrograms/0.5 microliters/side) or saline were infused into 3 different regions (dorsal, medial, ventral) of the rat globus pallidus, to examine their effects on locomotor activity. Locomotor activity of each rat was measured 45 min before and 90 min after saline or morphine pallidal microinjections. Morphine induced a dose-dependent increase in locomotion. This increase in locomotion was also significantly different between the 3 pallidal regions. Pretreatment with naloxone (1 mg/kg, sc) inhibited the morphine (7.5 micrograms) hyperlocomotion elicited from all three pallidal areas. The results suggest that the entire pallidum serves as substrate of morphine hyperlocomotion mediated by opiate receptors.
Anagnostakis
Y
Y
Department of Basic Sciences, Medical School, University of Crete, Heraklion, Greece.
Krikos
Y
Y
Spyraki
C
C
D000818:Animals; D002404:Catheterization; D004305:Dose-Response Relationship, Drug; D005917:Globus Pallidus / Q000033:anatomy & histology / Q000502:physiology*; D006185:Habituation, Psychophysiologic / Q000502:physiology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism; D017450:Receptors, Opioid, mu
D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D009270:Naloxone; D009020:Morphine