[Changes in the posture of healthy rats following intracranial administration of brain extracts from animals with experimental vestibulopathies].

A fraction consisting of low-molecular components (LMCs) was isolated from the brain of rats with unilateral destruction of the Deuters lateral vestibular nucleus (LVN) or with the generator of excitation (GE) created in the LVN with tetanus toxin. Intracranial administration of the preparation to normal rats produced the tension of body muscles, bending and opposite changes in the muscle tone of the hind limbs - the delay in the pulling up of the paw passively set aside and enhancement of the flexor tone of the opposite hind limb. The delayed pulling up of the hind paw in the recipients occurred on the side where the donors manifested an activated LVN (on the GE side or on the opposite side of the nucleus destruction). The effects cited did not occur if LMCs were exposed to proteolytic destruction or if the administration of LMCs was preceded by intraperitoneal injection of nalorphine, as well as if LMCs were administered in conjunction with naloxone. It is suggested that the test factors of the postural asymmetry are of peptide nature and that the opiate brain systems participate in the formation of the responses to their administration. A possible contribution of neurochemical lateralization of the brain to the phenomena of the "pathological condition transfer" is discussed.