Bombesin-induced changes of sensory transmission in the dorsal column nuclei

Bombesin was intracisternally administered to determine the effects on the neuronal activities of the dorsal column nuclei (DCN) of anesthetized rats. Although averaged afferent somatosensory transmission through 22 DCN neurons did not appear to be altered by bombesin (-1.11 +/- 3.5%), 12 of them were actually augmented (+17.15 +/- 2.7%) and 10 of them were suppressed (-26.15 +/- 4.9%) during 40 min after bombesin (0.01 microgram) administration. Pretreatment of a bombesin antagonist ([Leu13,Psi(CH2NH)Leu14]bombesin, 0.1 microgram) blocked the effects of bombesin. Lower dose (0.001 microgram) of bombesin did not exert any influences. These results suggest that bombesin may heterogeneously influence afferent somatosensory information in the brain stem of the rat.