Sweet and Salty Taste Responses in Alcohol‐preferring (P) and Alcohol‐Nonpreferring (NP) Rats

Naïve P rats showed increased mRNA and protein expression of T1R3 (a sweet taste receptor component) and TRPV1t (a putative benzamil (Bz)‐insensitive salt taste receptor) in the anterior tongue and small intestine mucosal cells relative to NP rats. We investigated if up‐regulation of receptors alter neural and behavior responses to sweet and salty stimuli in P rats. P rats showed a greater preference for 5% ethanol and 10% sucrose and greater chorda tympani (CT) taste nerve responses to sucrose, SC45647 and NaCl+Bz. Benzamil decreased NaCl preference in NP rats but not in P rats. A TRPV1t agonist, Maillard reacted peptides conjugated with galacturonic acid (GalA‐MRPs), decreased preference for NaCl+Bz in P but not in NP rats. In P rats the concentration‐CT response relation for ethanol and 0.5 M sucrose was higher and shifted to the left relative to NP rats. In naïve P rats and in NP rats chronically given 5% ethanol in a no choice paradigm, the concentration‐CT response relation for TRPV1t agonists (resiniferatoxin and GalA‐MRPs) and NaCl+Bz was enhanced and shifted to the left relative to naïve NP rats, but was unchanged in P rats. In NP rats, TRPV1t activity was increased by forced alcohol consumption to levels comparable to those of P rats. We conclude that chronic alcohol ingestion alters sweet and salt taste responses and may affect chemoreception in the gastrointestinal tract as well. Supported by DC‐000122 and DC‐005981.