[The sensorimotor reactivity of rats with an initially high anxiety-phobia level]

Sensorimotor response was measured by acoustic startle reflex in Wistar male rats with innate high and low levels of anxiety. The levels of anxiety were determined using a complex multiparameter method for evaluating anxiety-phobic states in rats by a ranged scale. Amplitude and prepulse inhibition of the acoustic startle response were increased, but latency of the startle reflex was decreased in rats with innate high level of anxiety as compared with those with innate low level. In rats with innate high level of anxiety injection of subconvulsive doses of pentylenetetrazol (10 and 15 mg/kg i.p.) resulted in an increase of the amplitude of the acoustic startle response and, additionally (under the dose 10 mg/kg) in a decrease of its latency. Facilitation of acoustic startle in rats with innate high level of anxiety is suggested to reflect either a deficit of inhibitory, or intensification of excitatory modulating influences on signal transmission in nerve circuit of acoustic startle. Studies of the sensorimotor response by acoustic startle in rats with innate high level of anxiety are believed to be useful for elucidating basic mechanisms of anxiety and phobia.