Potentiation by vestibular stimulation of the immobility reflex elicited by clamping in developing and adult rats

We have previously described (Exp. Neurol., 97:315-326, 1987) that clamping of the neck elicits a profound immobility with flexion of limbs and ventroflexion of head and neck ('carrying posture'). We also observed that when a clamped rat pup is carried by the experimenter's hand, such carrying posture was potentiated. In the present paper we observed that in adult rats vestibular stimulation by circular acceleration potentiates the duration of immobility reflex by clamping and intensifies the limb flexion. In rat pups from 10 to 20 days, vestibular stimulation potentiated only the carrying posture but not the duration of the immobility reflex by clamping.