Alpha up-beta down adrenergic regulation: a possible mechanism of action of antidepressant treatments.
The presently reported findings: that spaced electroconvulsive treatment increases the density of alpha-1 adrenoceptor in the spinal cord as well as in the cerebral cortex of the rat, that treatment with various classes of antidepressant drugs, including antidepressant neuroleptics, affects in a similar manner alpha-adrenoceptors, elevating within 2 weeks the density of alpha-1, and depressing the density of alpha-2 subpopulation, and that prolonged imipramine treatment in investigated strains of rats does not depress the beta adrenoceptor density within 3 weeks, but only after 6-week-treatment such an effect is observed, are discussed together with our earlier results. It is suggested that the first effect of an antidepressant therapy may be a transient upregulation of alpha-2 adrenoceptors causing a decrease in noradrenaline utilization, but this is followed rapidly by an upregulation of alpha-1 adrenoceptors and depression of density of alpha-2 adrenoceptors. Eventually, adaptive beta adrenoceptor down-regulation follows. The final effect of an antidepressant therapy is a specific facilitation of neurotransmission regulated by alpha-1 adrenoceptors.
D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001923:Brain Chemistry / Q000187:drug effects; D003000:Clonidine / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D004597:Electroshock; D007099:Imipramine / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013116:Spinal Cord / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism
D000928:Antidepressive Agents; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D003000:Clonidine; D007099:Imipramine; D011224:Prazosin