Influence of sympathectomy on alpha 2 adrenoceptor binding sites in canine blood vessels.
The effects of denervation of alpha 2 adrenoceptor binding sites were examined in canine arteries and veins. Denervation of the lower abdominal aorta, renal and femoral arteries and femoral veins marked reduced vessel norepinephrine concentrations. Denervation had little effect on the concentration of alpha 2 adrenoceptor binding sites or the affinity of (3H)yohimbine for these sites. The apparent lack of any significant reduction in receptor binding sites suggests that the majority of these sites are located on smooth muscle cells of blood vessels. The failure of any appreciable rise in receptor concentration following denervation is consistent with the hypothesis from functional studies that postsynaptic alpha 2 adrenoceptors on blood vessels are located extra-synaptically and hence not influenced by neurally released norepinephrine.
D000818:Animals; D001012:Aorta, Abdominal / Q000378:metabolism; D001808:Blood Vessels / Q000294:innervation / Q000378:metabolism*; D004285:Dogs; D005263:Femoral Artery / Q000378:metabolism; D005268:Femoral Vein / Q000378:metabolism; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012077:Renal Artery / Q000378:metabolism; D013562:Sympathectomy; D015016:Yohimbine / Q000378:metabolism
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine