DIVERGENT RESPONSES TO LONG-TERM STRESSORS IN RAT LINES SELECTED FOR DIFFERENT FUNCTIONAL-STATES OF THE NERVOUS-SYSTEM

The conditioned and reflex parameters in rat lines selected for the th reshold of excitability (a fundamental characteristics of the function al state of the nervous system) were estimated. This measure is based on the response of the tibial nerve to electrical stimulation, which g ives a general indication of the level of excitability of other parts of the nervous system. Testing was made 1-3 days after 15 days of dail y stress caused by randomly presented pairing of light and unavoidable electric shock. Expression of the sensitivity to the electric current , and the reflex components of the behavior, depends on the geneticall y determined level of the functional state of the nervous system