Alterations in delta opioid receptor levels in discrete areas of the neocortex and in the globus pallidus of the aging guinea pig: a quantitative autoradiographic study.
The effect of aging on delta opioid receptors was examined in the brains of guinea pigs aged 1, 6, 24 and 36 months. Quantitative autoradiography was used to monitor the concentrations of delta receptors in various anatomical regions at five rostro-caudal levels. delta opioid receptor populations were found to be remarkably stable throughout the life span of this species. We have, however, discovered anatomical areas which offer striking exceptions. In the globus pallidus, progressive age-related losses of delta receptors reached 50% in the senescent animal. In contrast, laminae I, II of the lateral agranular frontal cortex and laminae I, II and III, IV of the primary somatosensory cortex demonstrated age-related increases in the concentrations of delta receptors ranging from 30 to 45%. These changes are discussed with the view to their being functionally related components of motor circuitry involving pyramidal and extrapyramidal elements.
Department of Psychiatry, New York University Medical Center, NY 10016.
J M
JM
Hiller
L Q
LQ
Fan
E J
EJ
Simon
D000375:Aging / Q000378:metabolism*; D000700:Analgesics / Q000493:pharmacokinetics; D000818:Animals; D001345:Autoradiography; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000378:metabolism*; D003342:Corpus Striatum / Q000033:anatomy & histology / Q000378:metabolism; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004745:Enkephalins / Q000493:pharmacokinetics; D005917:Globus Pallidus / Q000033:anatomy & histology / Q000378:metabolism*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D011869:Radioligand Assay; D017465:Receptors, Opioid, delta / Q000378:metabolism*
D000700:Analgesics; D004745:Enkephalins; D017465:Receptors, Opioid, delta; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004743:Enkephalin, Leucine; C034318:enkephalin, Ser(2), Leu(5), Thr(6)-