title: Effects of ruthenium red, quinacrine hydrochloride, ethacrynic acid and 2,4-dinitrophenol on the water receptor of the frog tongue.
abstract: Effects of some chemicals, which are known as inhibitors of Ca2+-dependent ATPases, on the water receptor of the frog tongue were examined by using single fungiform papilla preparations. When a sufficient amount of ruthenium red, quinacrine hydrochloride, ethacrynic acid or 2,4-dinitrophenol was added to the standard stimulating solution (5mM CaCl2+100 mM NaCl), which has been shown to stimulate sufficiently the water receptor of the frog tongue, no neural response was elicited. The concentrations necessary for 50% inhibition were approximately 3 X 10(-6)M for ruthenium red, 1 X 10(-5) M for quinacrine hydrochloride, 1 X 10 (-3) M for ethacrynic acid and 2 X 10(-4) M for 2,4-dinitrophenol. Organic mercurials, mersalyl acid and p-chloromercuribenzoic acid, had no effect on the nueral response, but repeated application of these chemicals led to a permanent depression in receptor activity. Ouabain had no effect on either the neural response or receptor activity. These observations indicate that the receptor molecule of the frog water receptor has a similar property to that of the Ca2+-dependent ATPase of red-cell membrane in respect to the susceptibility to inhibitors.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000818:Animals; D001386:Azides / Q000494:pharmacology; D002118:Calcium; D002628:Chemoreceptor Cells / Q000187:drug effects*; D003486:Cyanides / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology*; D004976:Ethacrynic Acid / Q000494:pharmacology*; D066298:In Vitro Techniques; D010042:Ouabain / Q000494:pharmacology; D011796:Quinacrine / Q000494:pharmacology*; D011898:Ranidae; D012430:Ruthenium Red / Q000494:pharmacology; D013997:Time Factors; D014059:Tongue / Q000294:innervation*; D014867:Water
chemical_list: D001386:Azides; D003486:Cyanides; D004140:Dinitrophenols; D014867:Water; D012430:Ruthenium Red; D010042:Ouabain; D000251:Adenosine Triphosphatases; D011796:Quinacrine; D004976:Ethacrynic Acid; D002118:Calcium