title: Possible contribution of pannexin channel to ATP-induced currents in vitro in vasopressin neurons isolated from the rat supraoptic nucleus.
abstract: Release of arginine vasopressin (AVP) from magnocellular neurosecretory cells (MNCs) of the supraoptic nucleus (SON) is controlled by the electrical activity of these neurons. ATP plays a crucial role in the regulation of SON MNCs by activating the purinergic P2X and P2Y receptors. Recent reports of interaction between P2X receptors and pannexin channels have provided new insights into the physiology of the central nervous system; however, the function of pannexin channels has not been assessed in AVP neurons. In the present study, we examined the possible contribution of the pannexin channel in ATP-induced responses in SON AVP neurons. We used the whole-cell patch-clamp technique in isolated rat SON MNCs that express an AVP-enhanced green fluorescent protein transgene. The ATP-induced current was inhibited in a concentration-dependent manner by pannexin channel blockers carbenoxolone and mefloquine, whereas the connexin channel blockers flufenamic acid and lanthanum had no effect. Multi-cell reverse transcriptase-polymerase chain reaction experiments confirmed the existence of pannexin-1 mRNA in AVP neurons. The involvement of the ATP-activated transient receptor potential vanilloid and acid-sensing ion channels was excluded. These results suggest that pannexin channels in SON AVP neurons are involved in the regulatory mechanisms of neuronal activity.
authors.affiliation: Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Ohbuchi
authors.forename: Toru
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Saito
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Ohkubo
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Toru
authors.initials: T
authors.lastname: Ishikura
authors.forename: Akiko
authors.initials: A
authors.lastname: Katoh
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fujihara
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Hideaki
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ueta
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017630:Connexins / Q000378:metabolism; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D055647:Rats, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013495:Supraoptic Nucleus / Q000502:physiology*; D014667:Vasopressins / Q000378:metabolism
chemical_list: D017630:Connexins; D007473:Ion Channels; D009419:Nerve Tissue Proteins; C479936:pannexin 1, rat; D014667:Vasopressins; D000255:Adenosine Triphosphate