Alpha 1-adrenoceptor denervation supersensitivity in brain: physiological and receptor binding studies.
Electrophysiological and radioligand binding methods were used to characterize noradrenergic denervation supersensitivity at alpha 1-adrenoceptors in rat thalamus. Denervation was accomplished either by intraventricular or intracerebral injection of the catecholamine neurotoxin 6-hydroxydopamine (6-OHDA). In the physiological studies, the sensitivity of single lateral geniculate neurons to norepinephrine, carbachol, and serotonin was compared in sham and lesioned animals various times after 6-OHDA. Conducted in parallel were radioligand binding studies in which the density and affinity of thalamic alpha 1-adrenoceptors were measured with the specific antagonist [3H]prazosin. The results indicate that denervation produces a selective increase in the sensitivity of geniculate neurons to alpha 1-adrenergic stimulation and a concomitant increase in alpha 1-adrenoceptor density and agonist affinity.
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D003714:Denervation; D005071:Evoked Potentials / Q000187:drug effects; D005829:Geniculate Bodies / Q000187:drug effects / Q000502:physiology*; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D016627:Oxidopamine; D011224:Prazosin / Q000378:metabolism*; D011799:Quinazolines / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology
D006892:Hydroxydopamines; D011799:Quinazolines; D011941:Receptors, Adrenergic; D012701:Serotonin; D016627:Oxidopamine; D002217:Carbachol; D009638:Norepinephrine; D011224:Prazosin