Amiloride sensitivity in the neonatal rat.
Amiloride-sensitive sodium channels in taste buds appear to play a key role in the response to NaCl stimulation, at least in adult rats. The researchers examined whether neonatal rats, which display an exaggerated preference for hypertonic NaCl solutions, lack functional amiloride-sensitive sodium channels. NaCl intake was significantly reduced by amiloride pretreatment, but water and ammonium chloride, NH4Cl, were unaffected. The researchers assessed whether the early appearance of amiloride sensitivity was mediated by effects on chorda tympani (CT) activity by sectioning the CT before testing. CT transection reduced intake of NaCl solutions and eliminated evidence of amiloride sensitivity. Amiloride sensitivity was also assessed by recording of whole-nerve CT activity at 8-11 days of age; the response to NaCl stimulation was significantly suppressed by amiloride. These data indicate that amiloride-sensitive sodium channels develop earlier than previously believed.
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Department of Psychology, University of Washington.
Bernstein
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D000367:Age Factors; D000584:Amiloride / Q000494:pharmacology*; D000643:Ammonium Chloride / Q000008:administration & dosage; D000818:Animals; D000831:Animals, Newborn; D002814:Chorda Tympani Nerve / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D005518:Food Preferences / Q000187:drug effects*; D051381:Rats; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage*; D015222:Sodium Channels / Q000187:drug effects*; D013649:Taste / Q000187:drug effects; D013650:Taste Buds / Q000187:drug effects*
D012462:Saline Solution, Hypertonic; D015222:Sodium Channels; D000643:Ammonium Chloride; D000584:Amiloride