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O2-sensitive K+ currents in carotid body chemoreceptor cells from normoxic and chronically hypoxic rats and their roles in hypoxic chemotransduction.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Wyatt, Christopher N. Wright, Craig Steven Bee, David Peers, Chris S. |
| Copyright Year | 1995 |
| Abstract | Carotid body-mediated ventilatory increases in response to acute hypoxia are attenuated in animals reared in an hypoxic environment. Normally, O2-sensitive K+ channels in neurosecretory type I carotid body cells are intimately involved in excitation of the intact organ by hypoxia. We have therefore studied K+ channels and their sensitivity to acute hypoxia (PO2 12-20 mmHg) in type I cells isolated from neonatal rats born and reared in normoxic and hypoxic environments. When compared with cells from normoxic rats, K+ current density in cells from hypoxic rats was significantly reduced, whereas Ca2+ current density was unaffected. Charybdotoxin (20 nM) inhibited K+ currents in cells from normoxic rats by approximately 25% but was without significant effect in cells from hypoxic rats. However, hypoxia caused similar, reversible inhibitions of K+ currents in cells from the two groups. Resting membrane potentials (measured at 37 degrees C using the perforated-patch technique) were similar in normoxic and hypoxic rats. However, although acute hypoxia depolarized type I cells of normoxic rats, it was without effect on membrane potential in type I cells from hypoxic animals. Charybdotoxin (20 nM) also depolarized cells from normoxic rats. Our results suggest that type I cells from chronically hypoxic rats, like normoxic rats, possess O2-sensing mechanisms. However, they lack charybdotoxin-sensitive K+ channels that contribute to resting membrane potential in normoxically reared rats, and this appears to prevent them from depolarizing (and hence triggering Ca2+ influx and neurosecretion) during acute hypoxia. |
| Starting Page | 170 |
| Ending Page | 175 |
| Page Count | 6 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.pnas.org/content/92/1/295.full.pdf |
| PubMed reference number | 7529413v1 |
| Volume Number | 92 |
| Issue Number | 1 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Carotid Body Carotid Stenosis Charybdotoxin Excitation Hypoxia Membrane Potentials Neurosecretion PO-2 Potassium Psychological inhibition Rest torr |
| Content Type | Text |
| Resource Type | Article |
