Inducement of Sechenov inhibition by EtOH and NA in the Bufo toad

Central inhibition, discovered by Sechenov in 1862, suggests that electrically stimulating the forebrain or medulla oblongata in frog generally suppresses reflexes. However, the underlying molecular mechanisms are still unclear. Using ethanol (EtOH), noradrenalin (NA), and other neurotransmitters in thalamic preparations, Sechenov inhibition was stimulated in Bufo toads in this study. The result showed that, similar to Sechenov inhibition, the acute application of EtOH or NA excited the thalamus and prolonged the latency of withdrawal reflex. Our study evidences the involvement of α-adrenoceptors in such central inhibition, and explains the role of acute EtOH application in the induction of reflex inhibition. Contributed equally to this work Supported by the Major State Basic Research Development Program of China (973 Program) (Grant No. 2005CB522503)