Iturriaga R, Mokashi A, Lahiri S
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia 19104-6085, USA.
J Auton Nerv Syst. 1998 May 28;70(1-2):23-31. doi: 10.1016/s0165-1838(98)00019-8.
In order to test the hypothesis that carotid body (CB) chemoreception depends on the functions of anion channels and HCO3-/Cl- exchangers, we studied the effects of the anion channel blocker anthracene-9-carboxylic acid (9-ANC), the carbonic anhydrase inhibitor methazolamide, and the HCO3-/Cl- exchanger blocker 4,4 diisothiocyanatostilbene-2-2'disulfonic acid (DIDS) on the chemosensory discharges of cat CB, perfused-superfused in vitro at 36.5 +/- 0.5 degrees C, with a modified Tyrode solution. The chemosensory responses to hypoxia (PO2 approximately 50 Torr), hypercapnia (PCO2 approximately 60 Torr, pH = 7.10), nicotine (2-4 nmol) and NaCN (20-40 nmol) were recorded. 9-ANC (2 microM) and DIDS (10 microM) decreased the chemosensory baseline activity, and eliminated the initial peak responses to hypercapnia and hypoxia and increased the time to achieve it. Methazolamide (0.13 mM) did not alter the effect of 9-ANC. The steady state responses to hypoxia and hypercapnia were not diminished after 9-ANC but DIDS lowered the responses. Responses to NaCN effects were all diminished but those to nicotine were not affected. The results suggest that the functions of anion channels and HCO3-/Cl- exchangers are important for the resting dischargers and for the fast responses to hypoxia and hypercapnia.
为了验证颈动脉体（CB）化学感受依赖于阴离子通道和HCO3-/Cl-交换体功能的假说，我们研究了阴离子通道阻滞剂蒽-9-羧酸（9-ANC）、碳酸酐酶抑制剂甲唑酰胺以及HCO3-/Cl-交换体阻滞剂4,4'-二异硫氰酸芪-2,2'-二磺酸（DIDS）对猫CB化学感受性放电的影响。猫CB在36.5±0.5℃下用改良的台氏液进行体外灌流-超灌流。记录了对低氧（PO2约50 Torr）、高碳酸血症（PCO2约60 Torr，pH = 7.10）、尼古丁（2 - 4 nmol）和氰化钠（20 - 40 nmol）的化学感受反应。9-ANC（2 μM）和DIDS（10 μM）降低了化学感受基线活动，消除了对高碳酸血症和低氧的初始峰值反应，并延长了达到峰值的时间。甲唑酰胺（0.13 mM）未改变9-ANC的作用。9-ANC作用后对低氧和高碳酸血症的稳态反应未减弱，但DIDS降低了这些反应。对氰化钠作用的反应均减弱，但对尼古丁的反应未受影响。结果表明，阴离子通道和HCO3-/Cl-交换体的功能对于静息放电以及对低氧和高碳酸血症的快速反应很重要。
