Voltage-Dependent K Channels in Mouse Glomus Cells are Modulated by Acetylcholine
Several neurotransmitters are present in the carotid body. These neurotransmitters are responsible to evoke action potentials in afferent nerve endings. They also modify the function of glomus cells, by binding to autoreceptors on glomus cells. We have previously demonstrated that ACh variably influences voltage-dependent K (Kv) current in cat glomus cells (Shirahata et al., 2002). Excitability of glomus cells are regulated by several types of K channels including voltage-dependent (Kv) channels (Buckler, 1999; Shirahata and Sham, 1999). Kv channels are activated with membrane depolarization, and play an essential role for repolarizing the cell membrane. Several studies have shown that the activity of Kv channels are modulated by neurotransmitters (Brown et al., 1997; Dong and White, 2003; Fukuda et al., 1988; Huang et al., 1993; Shi et al., 1999, 2004), and this type of modification may be important for fine tuning of the excitability of glomus cells. Recent studies have shown that the carotid body of DBA/2J inbred strain of mice demonstrates morphological similarities to cat glomus cells (Yamaguchi et al., 2003). Glomus cells of these mice responds to ACh (Yamaguchi et al., 2003) and express 4-aminopyridine sensitive and charybdotoxin sensitive components of Kv channels (Yamaguchi et al., 2004). In this study, we have investigated whether Kv channels in glomus cells of DBA/2J mice are also modified by ACh. Further, some underlying mechanisms of Kv current modulation by ACh was also investigated.
KeywordsCarotid Body Krebs Solution Tyrode Solution Glomus Cell Cholinergic Modulation
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