Dedov V N, Roufogalis B D
Department of Pharmacy, University of Sydney, NSW, Australia.
Neurosci Lett. 1998 Jun 5;248(3):151-4. doi: 10.1016/s0304-3940(98)00351-6.
Capsaicin (1 microM) evoked [Ca2+]i transients in two-thirds of a Percoll-gradient enriched population of rat dorsal root ganglion (DRG) neurones. Amongst the capsaicin-sensitive neurones, 68% responded to capsaicin with peak [Ca2+]i transients of 681 +/- 67 nM, whereas the remaining neurones gave peak [Ca2+]i transients of 260 +/- 84 nM. In the presence of Mn2+ in Ca2+-free medium, capsaicin evoked quenching of fura-2 fluorescence, due to Mn2+ influx, in a similar proportion of neurones. Two patterns of capsaicin-sensitive Mn2+ quenching were observed: 72% of neurones showed rapid quenching (t1/2 of 18.3 +/- 4.1 s), whereas the remaining neurones had low quenching rates (t1/2 of 119 +/- 33 s). Distinct capsaicin-sensitive subpopulations of DRG neurones can thus be distinguished on the basis of their peak [Ca2+]i transient amplitudes, which appear to be associated with different rates of Ca2+ influx.
辣椒素（1微摩尔）可在经Percoll梯度富集的大鼠背根神经节（DRG）神经元群体的三分之二中诱发[Ca2+]i瞬变。在对辣椒素敏感的神经元中，68%的神经元对辣椒素的反应是[Ca2+]i瞬变峰值为681±67纳摩尔，而其余神经元的[Ca2+]i瞬变峰值为260±84纳摩尔。在无钙培养基中存在Mn2+的情况下，辣椒素会在相似比例的神经元中诱发fura-2荧光猝灭，这是由于Mn2+内流所致。观察到两种辣椒素敏感的Mn2+猝灭模式：72%的神经元表现出快速猝灭（半衰期为18.3±4.1秒），而其余神经元的猝灭速率较低（半衰期为119±33秒）。因此，DRG神经元的不同辣椒素敏感亚群可根据其[Ca2+]i瞬变峰值幅度来区分，这些幅度似乎与不同的Ca2+内流速率相关。
