Trigeminal reflexes and ingestive behavior in the rat.

Used photographic, eletrophysiological, and neurobehavioral analyses in 3 experiments with 21 Wistar rats to examine the contribution of trigeminally mediated jaw-opening reflexes to the control of ingestive behavior. During eating and drinking, jaw opening was always preceded by a period of perioral contact with the food or water source (Exp I). Electrical and mechanical stimulation of perioral areas in Ss that were anesthetized with chlorprothixene (0.3 ml) and either ketamine HCl (0.05 ml/100 g) or chloralose (80 mg/kg) elicited jaw-opening reflexes (recorded from the mylohyoid nerve trunk) at short latencies and low stimulus intensities (Exp II). Trigeminal orosensory deafferentation (sparing jaw muscle afferents and efferents, taste, vision, and olfaction) abolished or significantly reduced mouth opening during eating or drinking (Exp III). It is concluded that motivational processes operate through trigeminal reflexes to generate eating in rats. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)