Hyperpolarization-activated Cl- current elicited by pituitary adenylate cyclase activating polypeptide in Xenopus oocytes.
We examined the electrophysiological effect of pituitary adenylate cyclase activating polypeptide (PACAP) in isolated Xenopus laevis oocytes in vitro. In conventional two-electrode voltage clamp experiments, PACAP (1-10 microM) activated an inward rectifier current at membrane potentials more negative than -60 mV without causing any significant change in currents at potentials more positive than -60 mV both in the follicle-enclosed oocyte and in the defolliculated oocyte. This current reversed at -22.5 mV, close to the theoretical value of Cl- equilibrium potential and the reversal potential of this current was shifted positively by reducing [Cl-]o. This current was blocked by Cl- channel blocker SITS and Ba2+. Furthermore, VIP and adenylate cyclase activator forskolin did not elicit the currents. In conclusion, PACAP elicited the hyperpolarization-activated Cl- current in Xenopus laevis oocytes. This current may modulate the membrane potential of the oocyte, thereby affecting the oocyte physiology.
Kato
M
M
Department of Physiology I, Nippon Medical School, Tokyo, Japan. mkato@nms.ac.jp
Hanaoka
Y
Y
Tatemoto
K
K
Kimura
C
C
D000818:Animals; D018118:Chloride Channels / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D005260:Female; D008564:Membrane Potentials / Q000187:drug effects; D009479:Neuropeptides / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D006080:Ovarian Follicle / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011986:Receptors, Somatotropin / Q000187:drug effects; D018005:Receptors, Vasoactive Intestinal Peptide / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D029867:Xenopus Proteins; D014982:Xenopus laevis
C495404:ADCYAP1 protein, Xenopus; D018118:Chloride Channels; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011986:Receptors, Somatotropin; D018005:Receptors, Vasoactive Intestinal Peptide; D029867:Xenopus Proteins; D014660:Vasoactive Intestinal Peptide