title: alpha 1- and alpha 2-adrenoceptors in rat cerebral cortex: effect of frontal lobotomy.
abstract: Surgical noradrenergic denervation of the cortex via frontal lobotomy was used to destroy the noradrenergic nerve endings and thus give some insight into the distribution of alpha-adrenoceptors. Frontal lobotomy caused a reduction in noradrenaline content in rat cerebral cortex (2.1 +/- 0.4 ng/mg protein for lesioned side, 6.0 +/- 0.3 mg/mg protein for non-lesioned side), indicating an effective noradrenergic denervation. The differences in 3H-clonidine and 3H-prazosin binding observed following surgery were a significant decrease in the number of alpha 2-adrenoreceptors (115.0 +/- 4.5 to 91.7 +/- 3.2 fmol/mg protein, n = 7, P less than 0.001) and a smaller but significant increase in the number of alpha 1-adrenoceptors (119.7 +/- 2.5 to 131.6 +/- 5.4 fmol/mg protein, n = 7, P less than 0.05) in the lesioned cortex. Results of this study indicate that alpha 2-adrenoceptors located on presynaptic noradrenergic terminals represent only a small proportion of the total alpha 2-adrenoceptors in rat cerebral cortex.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002540:Cerebral Cortex / Q000032:analysis* / Q000378:metabolism; D003000:Clonidine / Q000378:metabolism; D005625:Frontal Lobe / Q000601:surgery; D008297:Male; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011941:Receptors, Adrenergic / Q000032:analysis*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis* / Q000378:metabolism; D013562:Sympathectomy
chemical_list: D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D003000:Clonidine; D011224:Prazosin