title: In vivo labeling of dopamine receptors: light microscopic localization at the cellular level by means of dipping autoradiography with the agonist (3H)N-n-propylnorapomorphine.
abstract: A convenient method is described for light microscopic autoradiography at the cellular level for the visualization of in vivo labeled dopamine receptors. (3H)N-n-propylnorapomorphine [(3H)NPA] is administered to rats under conditions that are known to give specific and saturable accumulation in the striatum. Seventy minutes after intravenous administration, the brain is rapidly frozen and cut on a cryostate microtome. The sections are treated with formaldehyde vapor, defatted for 1 hour in xylene and dipped in liquid nuclear emulsion, exposed for 2 weeks and developed. Autoradiograms obtained in this way show a high silver grain density over the striatum and a low density over adjacent external capsule and neocortex. There was a sharp delineated boundary between striatum and adjacent external capsule. Since low energy radiation can be quantified in liquid emulsion autoradiograms, we counted silver grains in a number of regions. The distribution of silver grains appeared to be identical with the distribution of radioactive label after similar in vivo administration of (3H)NPA in other studies.
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives*; D001345:Autoradiography / Q000379:methods; D002540:Cerebral Cortex / Q000032:analysis*; D003342:Corpus Striatum / Q000032:analysis*; D004298:Dopamine / Q000378:metabolism; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009714:Nucleus Accumbens / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000032:analysis* / Q000187:drug effects
chemical_list: D011954:Receptors, Dopamine; C009074:N-n-propylnorapomorphine; D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine