[Neuromuscular excitation and pain sensitivity of rats with various levels of arterial pressure].

Responses to electric shock stimulation were studied in spontaneously hypertensive (SHR) and normotensive (WKY) rats. Neuro-muscular excitability and the pain thresholds were higher in the SHR rats. The decrease in the pain sensitivity seemed to be connected with changes of neuro-muscular excitability in hypertensive animals. The SHR rats were more active in new environment. Weak electric shocks reduced motor activity in the SHR rats more than in the WKY rats. Strong electric shocks enhanced motor activity and eliminated the strain and sex differences. The painful electric stimulation elicited a more obvious jumping activity in the SHR rats and a more active vocalisation in the WKY rats.