Role of BK Channels in Murine Carotid Body Neural Responses in vivo
The aim of this study was to explore the role of BK channels in the hypoxic sensitivity of the in vivo murine carotid body (CB). Four strains of mice (DBA/2J, A/J, BKα1 knockout and BKα1 wild type – FVB background) were used. The mice were anesthetized, paralyzed and mechanically ventilated (PaCO2 ~ 35 mmHg, PO2 > 300 mmHg). We measured carotid sinus nerve (CSN) activity during three gas challenges (FIO2: 0.21, 0.15 and 0.10). CSN activity was analyzed with time-variant spectral analysis with frequency domain conversion (Fast Fourier Transforms). Afferent CSN activity increased with lowering FIO2 in the DBA/2J, BKKO and BKWT mice with the most robust response in 600–800 frequencies. No substantial changes were observed in the A/J mice. Although maximal neural output was similar between the BKKO and BKWT mice, the BKWT had a higher early response compared to BKKO. Thus, BK channels may play a role in the initial response of the CB to hypoxia. The contribution of BKβ subunits or the importance of frequency specific responses was unable to be determined by the current study.
KeywordsBK channel Carotid sinus nerve Chemosensitivity Hypoxia Mouse
This work was funded, in part, by HL081345 and F31HL096450.
- He L, Dinger B, Sanders K, Hoidal J, Obeso A, Stensaas L, Fidone S, Gonzalez C (2005) Effect of p47phox gene deletion on ROS production and oxygen sensing in mouse carotid body chemoreceptor cells. Am J Physiol 289:L916–L924Google Scholar
- Pérez-García MT, Colinas O, Miguel-Velado E, Moreno-Domínguez A, López-López JR (2004) Characterization of the Kv channels of mouse carotid body chemoreceptor cells and their role in oxygen sensing. J Physiol 557:457–471Google Scholar
- Sanchez D, Lopez-Lopez JR, Perez-Garcia MT, Sanz-Alfayate G, Obeso A, Ganfornina MD, Gonzalez C (2002) Molecular identification of Kv subunits that contribute to the oxygen-sensitive K+ current of chemoreceptor cells of the rabbit carotid body. J Physiol 542:369–382Google Scholar
- Williams BA, Buckler KJ (2004) Biophysical properties and metabolic regulation of a TASK-like potassium channel in rat carotid body type 1 cells. Am J Physiol Lung Cell Mol Physiol 286:L221–L230Google Scholar