Shark pit organs: response to chemicals.
Nerve fibers from pit organs and canal neuromasts are distinguished by the nature of their electrophysiological response to mechanical and chemical stimulation. Pit organs respond to touch but have a relatively high threshold compared with canal neuromasts. They respond readily to sodium and potassium chloride solutions, the rate of discharge increasing with the concentration of the solution. Order of effectiveness with 1 molar solutions of monovalent cations is as follows: potassium, rubidium > sodium, ammonium > cesium, lithium. Anions are ineffective. Divalent cations such as calcium and magnesium are inhibitory. Responses to acid, sugar, and quinine are either very slight or inhibitory.
D000818:Animals; D002586:Cesium / Q000494:pharmacology; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D008094:Lithium / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D011189:Potassium Chloride; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012413:Rubidium / Q000494:pharmacology; D012754:Sharks / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology*; D012965:Sodium Chloride; D013650:Taste Buds / Q000187:drug effects / Q000502:physiology*
D000644:Quaternary Ammonium Compounds; D002586:Cesium; D012965:Sodium Chloride; D011189:Potassium Chloride; D008094:Lithium; D012964:Sodium; D012413:Rubidium; D011188:Potassium