K+ channel currents in rat ventral prostate epithelial cells.
BACKGROUND
Electrophysiological function of the normal prostate has not been extensively studied. In particular, ion channel currents and their regulation have not been studied in freshly-isolated prostate cells.


METHODS
Rat prostate secretory epithelial (RPSE) cells were isolated by collagenase treatment. Columnar epithelial cells were used for nystatin-perforated, whole-cell voltage clamp, and the intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured using fura-2.


RESULTS
Step-like depolarizing pulses (900 msec) starting from - 90 mV induced outwardly rectifying K(+) currents without inactivation. ACh (10 microM) or ATP (100 microM) increased the outward current and hyperpolarized the cell membrane potential. Ionomycin (0.1 microM), a Ca(2+) ionophore, induced a similar increase in the outward current. TEA (5 mM), charybdotoxin (50 nM), and iberiotoxin (30 nM) inhibited the effect of ACh (or ATP) on the outward current, whereas apamin (100 nM) had no effect. The [Ca(2+)](i) of RPSE cells was increased by ACh, ATP, and UTP.


CONCLUSIONS
RPSE cells have iberiotoxin-sensitive Ca(2+)-activated K(+) channels that may play an important role in the exocrine secretions of the prostate.
Kim
Jun Hee
JH
Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea.
Hong
Eun-Kyung
EK
Choi
Hee Sook
HS
Oh
Seung-Joon
SJ
Kim
Kwang Myung
KM
Uhm
Dae-Yong
DY
Kim
Sung Joon
SJ
D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology; D004553:Electric Conductivity; D004847:Epithelial Cells / Q000502:physiology; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000819:agonists / Q000187:drug effects / Q000502:physiology*; D011467:Prostate / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015221:Potassium Channels; D000255:Adenosine Triphosphate; D000109:Acetylcholine; D002118:Calcium