Neuronal location of N6-cyclohexyl[3H]adenosine binding sites in rat and guinea-pig brain.
N6-cyclohexyl[3H]adenosine, ([3H]CHA), was used to label adenosine A1 receptors in crude synaptic membranes prepared from rat and guinea pig brain. The density of [3H]CHA binding sites was highest in the rat hippocampus and cerebellum and in the guinea-pig hippocampus. A micro-dissection of coronal sections of guinea-pig hippocampus revealed that the specific binding capacity for [3H]CHA in area CA-1 was 20-30% higher than in area CA-3, dentate gyrus and subiculum. Selective neuronal lesions of serotonergic, noradrenergic and cholinergic afferents to the hippocampus failed to alter [3H]CHA binding to hippocampal membranes. These results suggest that [3H]CHA binding sites are not associated with axons or terminals of these neurones in the hippocampus. Intrahippocampal injection of kainic acid reduced the number of [3H]CHA recognition sites by 30% with no alteration in the affinity of [3H]CHA for these receptors. Thus, a significant portion of A1 receptors may be associated with intrinsic neurones of the hippocampus which do not appear to be innervated by noradrenergic, cholinergic or serotonergic axons.
D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D006168:Guinea Pigs; D006624:Hippocampus / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009474:Neurons / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011983:Receptors, Purinergic; D013116:Spinal Cord / Q000378:metabolism; D013570:Synaptic Membranes / Q000378:metabolism
D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; C027513:N(6)-cyclohexyladenosine; D000241:Adenosine