The effects of n-alcohols on evoked synaptic potentials in rat hippocampal slices: Hill coefficients account for the cut-off phenomenon.
The anesthetic potencies of n-alcohols increase progressively with lengthening of the carbon chain and then disappear at a cut-off point of a longer-chain n-alcohol. In order to assess the mechanisms for cut-off in mammalian central nervous system, the effects of a series of n-alcohols (C(2)-C(11)) were examined on the evoked synaptic potentials of the rat hippocampal preparation in vitro. The n-alcohols (C(2)-C(10)) reduced the slope of the excitatory post-synaptic potential in a concentration-dependent manner, and the inhibitory potencies enhanced as a function of carbon chain length. The effect disappeared at n-undecanol (C(11)). The Hill coefficients of the concentration-response curves of the n-alcohols negatively correlated with the number of carbon atoms. The decrease in the Hill coefficient could account for the cut-off phenomenon, indicating that the results can support the anesthetic pocket hypothesis.
Takehana
K
K
Department of Anesthesiology, Toyama Medical and Pharmaceutical University School of Medicine, 2630 Sugitani, Toyama, Japan.
Hirota
K
K
Roth
S H
SH
Masuda
A
A
Ito
Y
Y
D000438:Alcohols / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D002244:Carbon / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects*
D000438:Alcohols; D002244:Carbon