title: Voltage-dependent ion channel currents in putative neuroendocrine cells dissociated from the ventral prostate of rat.
abstract: Prostate neuroendocrine (NE) cells play important roles in the growth and differentiation of the prostate. Following enzymatic digestion of rat ventral prostate, the whole-cell patch-clamp technique was applied to dark, round cells that exhibited chromogranin-A immunoreactivity, a representative marker of NE cells. Under zero current-clamp conditions, putative NE cells showed hyperpolarized resting membrane potentials of some -70 mV, and spontaneous action potentials were induced by an increase in external [K+] or by the injection of current. Using a CsCl pipette solution, step-like depolarization activated high-voltage-activated Ca2+ current (HVA I(Ca)) and tetrodotoxin-resistant voltage-activated Na+ current. The HVA I(Ca) was blocked by nifedipine and omega-conotoxin GVIA, L-type and N-type Ca2+ channel blockers, respectively. Using a KCl pipette solution, the transient outward K+ current (I(to)), Ca2+ -activated K+ currents (I(K,Ca)), the non-inactivating outward current and an inwardly rectifying K+ current (I(Kir)) were identified. I(K,Ca) was suppressed by charybdotoxin (50 nM), iberiotoxin (10 nM) or clotrimazol (1 microM), but not by apamine (100 nM). I(to) was inhibited by 4-aminopyridine (5 mM). I(Kir) was identified as a Ba2+ -sensitive inwardly rectifying current in the presence of a high-K+ bath solution. The voltage- and Ca2+ -activated ion channels could play significant roles in the regulation of neurohormonal secretion in the prostate.
authors.affiliation: Department of Physiology Sungkyunkwan University School of Medicine, 440-746, Suwon, Korea.
authors.forename: Jun Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Shin
authors.forename: Sang Soon
authors.initials: SS
authors.lastname: Yun
authors.forename: Tae Jin
authors.initials: TJ
authors.lastname: Kim
authors.forename: Seung-June
authors.initials: SJ
authors.lastname: Oh
authors.forename: Kwang Myung
authors.initials: KM
authors.lastname: Kim
authors.forename: Young-Shin
authors.initials: YS
authors.lastname: Chung
authors.forename: Eun-Kyoung
authors.initials: EK
authors.lastname: Hong
authors.forename: Dae-Yong
authors.initials: DY
authors.lastname: Uhm
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D018999:Charybdotoxin / Q000494:pharmacology; D053379:Chromogranin A; D002864:Chromogranins; D004553:Electric Conductivity; D005455:Fluorescent Antibody Technique; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009490:Neurosecretory Systems / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011467:Prostate / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D053379:Chromogranin A; D002864:Chromogranins; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D015222:Sodium Channels; D018999:Charybdotoxin; D013779:Tetrodotoxin; D011188:Potassium