Electroconvulsive therapy and the alpha-2 noradrenergic receptor: implications of treatment schedule effects.
Six factorially designed studies evaluated the effects of different schedules of electroconvulsive shocks (ECSs) on alpha-2 adrenoceptor function in the rat brain. Attenuation of the hypomotility response to a clonidine challenge was taken to indicate alpha-2 adrenoceptor downregulation, a putative mediator of antidepressant action. Six daily and six alternate-day ECSs were shown separately to produce this receptor change. Three alternate-day ECSs produced comparable downregulation for a comparable period as six daily ECSs; this suggests that ECS produces time-dependent effects. No changes were elicited with a single ECS, which indicates that a single ECS may not influence alpha-2 receptor function. Three daily ECSs produced brief downregulation, which has implications for receptor dynamics as a function of the ECS schedule. Finally, maintenance ECSs sustained alpha-2 adrenoceptor downregulation over 6 weeks, which suggests a possible neurochemical basis for maintenance electroconvulsive therapy. The clinical relevance and scope for further research are discussed.
Andrade
C
C
Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bangalore, India. candrade@bgl.vsnl.net.in
Sudha
S
S
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D004565:Electroconvulsive Therapy / Q000009:adverse effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D018341:Receptors, Adrenergic, alpha-2; D003000:Clonidine