HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by López-López, J R Articles by Pérez-García, M T Search for Related Content PubMed PubMed Citation Articles by López-López, J R Articles by Pérez-García, M T

Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, Spain.

1. The electrical properties of chemoreceptor cells from neonatal rat and adult rabbit carotid bodies (CBs) are strikingly different. These differences have been suggested to be developmental and/or species related. To distinguish between the two possibilities, the whole-cell configuration of the patch-clamp technique was used to characterize the ionic currents present in isolated chemoreceptor cells from adult rat CBs. Since hypoxia-induced inhibition of O2-sensitive K+ currents is considered a crucial step in O2 chemoreception, the effect of hypoxia on the adult rat chemoreceptor cell currents was also studied. 2. Outward currents were carried mainly by K+, and two different components could be distinguished: a Ca(2+)-dependent K+ current (IK(Ca)) sensitive to Cd2+ and charybdotoxin (CTX), and a Ca(2+)-insensitive, voltage-dependent K+ current (IK(V)). IK(V) showed a slow voltage-dependent activation (time constant (tau) of 87.4 ms at -20 mV and 8.8 ms at +60 mV) and a very slow inactivation, described by the sum of two exponentials (tau 1 = 684 +/- 150 ms and tau 2 = 4.96 +/- 0.76 s at + 30 mV), that was almost voltage insensitive. The kinetic and pharmacological properties of IK(V) are typical of a delayed rectifier K+ channel. 3. Voltage-dependent Ca2+ currents (ICa) were present in nineteen of twenty-seven cells. TTX-sensitive Na+ currents were also observed in about 10% of the cells. 4. Low PO2 (< 10 mmHg) reduced the whole outward current amplitude by 22.17 +/- 1.96% (n = 27) at +20 mV. This effect was absent in the presence of Cd2+. Since low PO2 did not affect ICa, we conclude that hypoxia selectively blocks IK(Ca). 5. The properties of the currents recorded in adult rat chemoreceptor cells, including the specific inhibition of IK(Ca) by hypoxia, are similar to those reported in neonatal rat CB cells, implying that the differences between rat and rabbit chemoreceptor cells are species related.

This article has been cited by other articles:

				M. T. Perez-Garcia, O. Colinas, E. Miguel-Velado, A. Moreno-Dominguez, and J. R. Lopez-Lopez Characterization of the Kv channels of mouse carotid body chemoreceptor cells and their role in oxygen sensing J. Physiol., June 1, 2004; 557(2): 457 - 471. [Abstract] [Full Text] [PDF]

				Y.-L. Li, S.-Y. Sun, J. L. Overholt, N. R. Prabhakar, G. J. Rozanski, I. H. Zucker, and H. D. Schultz Attenuated outward potassium currents in carotid body glomus cells of heart failure rabbit: involvement of nitric oxide J. Physiol., February 15, 2004; 555(1): 219 - 229. [Abstract] [Full Text] [PDF]