Regional central nervous system densities of delta-opioid receptors in alcohol-preferring P, alcohol-nonpreferring NP, and unselected Wistar rats.
The densities of delta-opioid receptors in the central nervous system of alcohol-naive, adult, male, alcohol-preferring P, alcohol-nonpreferring NP, and Wistar rats were examined with the use of quantitative autoradiography. Slides with coronal 20-microm sections through the regions of interest were incubated in 5 nM [3H]-[D-Pen(2),D-Pen(5)]enkephalin (DPDPE) to label delta(1)-opioid receptor sites. Nonspecific binding was determined in the presence of 10 microM naloxone. Significant differences between the P and the NP rat lines were found in numerous cortical regions, the basolateral amygdala, and the posterior hippocampus, with 10%-20% lower [3H]-DPDPE binding found in the P line. In most regions examined, binding levels in the Wistar rats were intermediate between those of the P and the NP rats. Significantly lower [3H]-DPDPE binding levels in the P rat may indicate fewer delta(1)-opioid receptors or decreased binding affinity. The lower binding in certain limbic regions, such as the basolateral amygdala and posterior hippocampus, as well as cortical differences in the P rat may be associated with the divergent alcohol drinking behaviors found between the P and the NP lines.
Strother
W N
WN
Department of Psychiatry, Institute of Psychiatric Research, 791 Union Drive, Indianapolis, IN 46202-4887, USA. wstrothe@iupui.edu
Chernet
E J
EJ
Lumeng
L
L
Li
T K
TK
McBride
W J
WJ
D000428:Alcohol Drinking; D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000378:metabolism*; D002755:Choice Behavior; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D012016:Reference Values; D014018:Tissue Distribution
D017465:Receptors, Opioid, delta