Electrophysiological Recordings from the Chorda Tympani After Lingual Nerve Transections in Rats

Taste is an important part of our daily life, though as a sensory system it is not fully understood. The chorda tympani nerve (CT) sends taste information to the brain. Other sensations such as hot/cold, spicy and menthol are sent via the lingual nerve to the brain. Both nerves have fibers in fungiform taste papillae, but only the CT contacts the taste buds. One way to help understand function is to transect (sever) a nerve. In a previous study, smaller taste bud volume was observed 16 days after lingual nerve transections (LX) in rats (Omelian, et al., in press), even though the CT remained intact. Recovery of taste buds occurred approximately 50 days after surgery. To determine whether these changes in the tongue influence taste input, electrophysiological recordings of CT activity were performed after LX in adult rats. To obtain the recordings, the four basic tastes were applied to the tongue: sodium chloride (salty), citric acid (sour), sucrose (sweet) and quinine (bitter). Preliminary data in this ongoing study will be presented. Since taste bud size is reduced soon after LX, we expect the neural activity of the CT to be reduced 16 days after surgery, and the recovery of function would occur around 50 days after surgery. Differences from these expectations would suggest that neural activity does not correlate with taste bud volume size. However, reduction of response will reinforce the finding that the lingual nerve has a substantive role in taste