5-Hydroxytryptamine-activated single-channel currents recorded from murine neuroblastoma cells.
Differentiated murine neuroblastoma cells (NIE-115) have receptors for 5-hydroxytryptamine (5-HT), the activation of which either depolarizes or hyperpolarizes these cells with associated increases in input conductance. Ionophoresis of 5-HT on to NIE-115 cells elicits brief depolarization, but the 5-HT receptors rapidly desensitize during repeated application of 5-HT. The reversal potential of 5-HT-induced depolarization is ca. 0 mV. With the use of the improved patch clamp technique it is possible to record single ion channel currents activated by 5-HT from intact cells as well as isolated membrane patches. These currents are invariably inward at the resting potential (approximately 50 mV). The channel has a conductance of approximately 140 pS and reversal potential of approximately 0 mV in normal saline. The channels recorded from the intact cells reveal more than one kinetically distinguishable open and closed states. The kinetic properties of 5-HT channels recorded from excised patches of membrane (as outside-out) are different from those recorded from the intact cell. Possible explanations for such differences are presented.
Guharay
F
F
Ramsey
R L
RL
Usherwood
P N
PN
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D007473:Ion Channels / Q000187:drug effects* / Q000502:physiology; D007700:Kinetics; D009447:Neuroblastoma / Q000378:metabolism*; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*
D007473:Ion Channels; D012701:Serotonin