Substances in subthreshold concentrations under stress conditions can act as conditioned stimuli and trigger defense reactions.
The capacity of living systems to perceive low-intensity stimuli sometimes inducing protective reactions is still little studied. Incubation of neurons under conditions increasing the content of cAMP and Ca(2+) increases the amplitude of their responses to lidocaine (10(-3) M). After cell preconditioning with low concentrations of lidocaine (10(-15) M) under these conditions, the protective effects of "ineffective" concentrations were detected, because the response amplitude did not decrease. It was hypothesized that the basic amplitude responses retrieved by lidocaine in a concentration of 10(-3) M are memory traces about the effects of this compound in subthreshold concentrations.
Zapara
T A
TA
Engineering and Design Institute of Computer Science, Siberian Division of Russian Academy of Sciences, Russia. zap@kti.nsc.ru
Proskura
A L
AL
Ratushnyak
A S
AS
Shtark
M B
MB
Epstein
O I
OI
D000818:Animals; D002118:Calcium / Q000378:metabolism; D003216:Conditioning, Operant; D000242:Cyclic AMP / Q000378:metabolism; D008012:Lidocaine / Q000008:administration & dosage*; D008195:Lymnaea / Q000502:physiology*
D008012:Lidocaine; D000242:Cyclic AMP; D002118:Calcium