We studied the sensitivity of sensorimotor cortex neurons in rabbits to microiontophoretic administration of antibodies against acid fibroblast growth factor (anti-aFGF). Spontaneous activity and reaction of neurons to electrical stimulation of 'feeding centers' in the lateral hypothalamic area (LHA) were recorded. We analyzed impulse activity of 52 neurons in the sensorimotor cortex. It was shown that 14 neurons (25%) reacted to microiontophoresis of anti-aFGF (excitation and inhibition in 9 and 5 neurons, respectively). Microiontophoretic administration of anti-aFGF did not change the reaction (excitation or inhibition) of 27 neurons to electrical stimulation of LHA. Initially, 14 neurons did not response to LHA stimulation. After microiontophoretic administration of anti-aFGF, 6 of 14 neurons displayed pronounced reactions to electrical stimulation of LHA (excitation and inhibition in 2 and 4 neurons, respectively). These data suggest that aFGF plays an important physiological role in feeding motivations.