Presynaptic location and axonal transport of beta 1-adrenoreceptors in the rat brain.

Interruption of the ascending noradrenergic neurons of the locus coeruleus in the rat forebrain with 6-hydroxydopamine produced a progressive accumulation, proximal to the lesion, of tritiated dihydroalprenolol binding activity over 2 days. This accumulation could be blocked by interrupting the neurons closer to their cell bodies. Competitive binding studies with the beta 2 agonist Zinterol suggested that the accumulated beta-receptors were primarily of the beta 1 subtype. These results suggest that, in the rat brain, some beta 1-adrenoreceptors are located in presynaptic, noradrenergic locus coeruleus neurons and are transported in their axons.