title: Hyperpolarization-activated Cl- current elicited by pituitary adenylate cyclase activating polypeptide in Xenopus oocytes.
abstract: 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.
authors.affiliation: Department of Physiology I, Nippon Medical School, Tokyo, Japan. mkato@nms.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: Y
authors.initials: Y
authors.lastname: Hanaoka
authors.forename: K
authors.initials: K
authors.lastname: Tatemoto
authors.forename: C
authors.initials: C
authors.lastname: Kimura
mesh_terms: 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
chemical_list: 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