Comparison of [3H]clonidine and [3H]guanfacine binding to alpha 2 adrenoceptors in membranes from rat cerebral cortex.
[3H]Clonidine and a new phenylacylguanidine antihypertensive drug, [3H]guanfacine, bind with a high affinity to alpha 2 adrenoceptors in membranes from rat cerebral cortex. Dissociation curves for [3H]clonidine binding indicated the presence of high and low affinity binding sites, whereas with [3H]guanfacine, two components could be distinguished only with difficulty; the major part of the binding being to a high affinity component. Saturation experiments revealed that both ligands bind with similar high affinity but that [3H]guanfacine labels twice the number of sites labeled by [3H]clonidine.
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D003000:Clonidine / Q000378:metabolism*; D005260:Female; D016316:Guanfacine; D006146:Guanidines / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D010648:Phenylacetates / Q000378:metabolism*; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism*
D006146:Guanidines; D010648:Phenylacetates; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D016316:Guanfacine; D003000:Clonidine