[Effect of furosemide on the ampullar endolymphatic potential and endolymphatic Ca2+ activity].
The ampullar endolymphatic potential (AEP) and the endolymphatic Ca2+ activity were measured with double-barred Ca2+ selective microelectrodes in the experimental hydrops of guinea pigs. They showed 3.16 +/- 0.42 mV (n = 9) and (4.10 +/- 1.22) x 10(-4) M, respectively. The AEP decreased significantly at about 6 min after intravenous administration of 10 mg/kg furosemide. Its minimal value was 3.04 +/- 0.53 mV at about 40 min. But there was no significant difference between that and the value before injection. The Ca2+ activity increased significantly and reached (7.10 +/- 1.32) x 10(-4) M at about 60 min. The changes indicate that Ca2+ may play an important role in the mechanism of the furosemide test.
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D004232:Diuretics / Q000494:pharmacology; D004710:Endolymph / Q000378:metabolism / Q000502:physiology*; D018159:Endolymphatic Hydrops / Q000378:metabolism / Q000503:physiopathology*; D005665:Furosemide / Q000494:pharmacology*; D006168:Guinea Pigs; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes