title: A/J and C57BL/6J mice differ in chorda tympani responses to NaCl.
abstract: The molecular mechanisms of sodium taste transduction are not completely understood, especially those responsible for the portion of NaCl's taste in rodents that is not blocked by amiloride. As a prelude to conducting genetic analyses of peripheral NaCl taste responsiveness, we performed multiunit electrophysiological recordings from the chorda tympani (CT) nerve in C57BL/6J (B6) and A/J mice. Mice were anesthetized, the CT was accessed, and taste solutions were flowed over the tongue in order to measure the integrated whole-nerve response. NaCl was delivered before and during application of 100μM amiloride. Pre-amiloride responses were significantly larger in A/J than B6 mice for 1-8mM NaCl. Responses to NaCl were suppressed significantly by amiloride in both strains and to similar degrees. However, the size of the amiloride-insensitive NaCl response component was significantly larger in A/J mice than in B6 mice for NaCl at 2-16mM. These data help to explain the prior observation that the strains differ in behavioral taste thresholds for NaCl. Specifically, the results suggest that perception of sodium-specific taste by mice depends on the ratio of amiloride-sensitive and -insensitive responses in the CT, rather than on the absolute level of the whole-nerve response to NaCl or on the size of the amiloride-sensitive component alone. Because the B6 and A/J mice differed in the size of their amiloride-insensitive components, they may prove useful in future genetic work designed to characterize the underlying transduction mechanisms.
authors: Department of Physiology and Health Science, Ball State University, Muncie, IN 47306, USA.
authors: Chandra M
authors: CM
authors: Cherukuri
authors: Alexander A
authors: AA
authors: Bachmanov
authors: Stuart A
authors: SA
authors: McCaughey
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002814:Chorda Tympani Nerve / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004347:Drug Interactions; D062686:Epithelial Sodium Channel Blockers / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D062686:Epithelial Sodium Channel Blockers; D012965:Sodium Chloride; D000584:Amiloride