Transecting the gustatory branches of the facial nerve impairs NH sub(4)Cl vs. KCl discrimination in rats

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology Vol. 283; no. 3; pp. R739 - R747
• Main Authors: Geran, L C, Garcea, M, Spector, A C
• Format: Journal Article
• Language: English
• Published: 01.09.2002
• ISSN: 0363-6119
• DOI: 10.1152/ajpregu.00103.2002

Ammonium and potassium chloride share a common taste quality and an amiloride-insensitive route of transduction. An amiloride-sensitive pathway might also be partially activated by these salts, although very few studies have reported effects of amiloride on nonsodium salt perception. This experiment was designed to determine 1) whether rats could discriminate KCl from NH sub(4)Cl and, if discrimination was evident, whether performance was impaired with 2) amiloride or 3) gustatory nerve transection. Rats were trained to discriminate KCl from NH sub(4)Cl (n = 8) and NaCl from NH sub(4)Cl (n = 8). Amiloride (100 mu M) impaired NaCl vs. NH sub(4)Cl but not KCl vs. NH sub(4)Cl performance, whereas both groups showed significant impairments after transection of the chorda tympani (CT) and greater superficial petrosal (GSP) branches of the facial nerve. This suggests that rats can discriminate between KCl and NH sub(4)Cl and that this discrimination does not rely on an amiloride-sensitive mechanism but does depend on the CT and/or GSP nerves. This experiment supports the hypothesis that the facial nerve is important for salt taste recognition and discrimination.