title: Opioid mu and delta and dopamine receptor number changes in rat striatum during stress.
abstract: The question whether acute and repeated immobilization stress is accompanied by changes in the number of opioid mu- and delta- -receptor and that of dopamine receptor in the rat corpus striatum was studied. The number of opioid mu- and delta-receptors as well as that of dopamine receptors was estimated in corpus striatum of rats subjected either to a single (acute) immobilization stress (IMO) for 150 min or to identical repeated stress exposure for 7 or 40 consecutive days. The number of mu-receptors was estimated by the use of 3H-dihydromorphine binding (an agonist) or 3H-naloxone binding (an antagonist). Increased number of mu-receptors was found after acute IMO as estimated from the binding of both mu-specific ligands. However, the binding of 3H-dihydromorphine showed no changes after 7x and elevated mu-receptor number after 40x repeated IMO, although the binding of 3H-naloxone after 7x and 40x IMO was decreased. This paradoxical pattern might be explained by different affinity of both ligands to mu-receptor subpopulations (i.e. mu1- and mu2-receptors). In addition, the number of delta-receptors (assayed by 3H-D-Ala2,D-Leu5-enkephalin binding) was increased after acute as well as repeated (7x and 40x) IMO. The changes of dopamine receptor number (as measured from 3H-spiroperidol saturation analysis) correlated well with delta-receptor changes after 1x and 7x repeated IMO, but not after 40x IMO, since in the latter group the number of dopamine receptors decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Czechoslovakia.
authors.forename: P
authors.initials: P
authors.lastname: Zeman
authors.forename: M
authors.initials: M
authors.lastname: Alexandrová
authors.forename: R
authors.initials: R
authors.lastname: Kvetnansky
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000032:analysis*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000032:analysis*; D011957:Receptors, Opioid / Q000032:analysis*; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000378:metabolism*
chemical_list: D011954:Receptors, Dopamine; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu