TY - JOUR
T1 - Odorants suppress T- and L-type Ca2+ currents in olfactory receptor cells by shifting their inactivation curves to a negative voltage
AU - Kawai, Fusao
PY - 1999/12/30
Y1 - 1999/12/30
N2 - Mechanisms underlying suppression of T- and L-type Ca2+ currents (I(Ca,T) and I(Ca,L)) by odorants were investigated in newt olfactory receptor cells (ORCs) using the whole-cell version of the patch-clamp technique. Under voltage clamp, odorants (amyl acetate, limonene and acetophenone) reversibly suppressed I(Ca,T) and I(Ca,L). These currents disappeared completely within 150 ms following amyl acetate puffs, and recovered in approximately 1 s after the washout. Hyperpolarization of the membrane greatly relieved the odorant block of I(Ca,T) and I(Ca,L). The activation curves of both currents were not changed significantly by odorants, while their inactivation curves were shifted to negative voltages. Half-inactivation voltages of I(Ca,T) were -66 mV (control), -102 mV (amyl acetate), -101 mV (limonene) and -105 mV (acetophenone) (all 0.3 mM); those of I(Ca,L) were -33 mV (control), -61 mV (amyl acetate), -59 mV (limonene), and -63 mV (acetophenone) (all 0.3 mM). These phenomena are similar to the effects of local anesthetics on I(Ca) in various preparations and also similar to the effects of odorants on I(Na) in ORCs, suggesting that these types of suppression are caused by the same mechanism. Copyright (C) 1999 Elsevier Science Ireland Ltd.
AB - Mechanisms underlying suppression of T- and L-type Ca2+ currents (I(Ca,T) and I(Ca,L)) by odorants were investigated in newt olfactory receptor cells (ORCs) using the whole-cell version of the patch-clamp technique. Under voltage clamp, odorants (amyl acetate, limonene and acetophenone) reversibly suppressed I(Ca,T) and I(Ca,L). These currents disappeared completely within 150 ms following amyl acetate puffs, and recovered in approximately 1 s after the washout. Hyperpolarization of the membrane greatly relieved the odorant block of I(Ca,T) and I(Ca,L). The activation curves of both currents were not changed significantly by odorants, while their inactivation curves were shifted to negative voltages. Half-inactivation voltages of I(Ca,T) were -66 mV (control), -102 mV (amyl acetate), -101 mV (limonene) and -105 mV (acetophenone) (all 0.3 mM); those of I(Ca,L) were -33 mV (control), -61 mV (amyl acetate), -59 mV (limonene), and -63 mV (acetophenone) (all 0.3 mM). These phenomena are similar to the effects of local anesthetics on I(Ca) in various preparations and also similar to the effects of odorants on I(Na) in ORCs, suggesting that these types of suppression are caused by the same mechanism. Copyright (C) 1999 Elsevier Science Ireland Ltd.
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U2 - 10.1016/S0168-0102(99)00091-7
DO - 10.1016/S0168-0102(99)00091-7
M3 - Article
C2 - 10617316
AN - SCOPUS:0032725263
VL - 35
SP - 253
EP - 263
JO - Neuroscience Research
JF - Neuroscience Research
SN - 0168-0102
IS - 4
ER -