NK1R expression in the caudal Nucleus of the Solitary Tract (cNTS) during chronic hypoxia and chronic hypercapnia in the ratFASEB Journal (2007)
AbstractNeurokinin 1 receptors (NK1R) in the cNTS are involved in the hypoxic ventilatory response and also associated with areas of central CO2-sensitivity such as cNTS. We tested the hypothesis that chronic stimulation of either chemoreflex will increase NK1R expression in the cNTS. We acclimatized adult male rats to 7 days of hypobaric hypoxia (HX, PIO2 = 70 Torr, n = 6) or normobaric hypercapnia (HC, FICO2 = 5%, n = 6) and measured ventilatory responses with whole body plethysmography. In room air before acclimatization, V = 374 ± 44 ml/min*kg. After 7 days of HX, V = 1171 + 135 ml/min*kg and V = 642 ± 77 ml/min*kg after 7 days of HC. V in HC showed a tendency to decrease from 1045 ± 146 ml/min*kg on day 1. NK1R immunoreactivity (NK1R-ir) on 30 micron frozen transverse sections of cNTS was increased by 7 days of HX but not HC. NK1R-ir occurred mainly on fibers instead of cell bodies. Total NK1R protein measured in micropunches from the cNTS with Western blotting increased 197% in chronic HX (n=6) and similar experiments are being done for chronic HC. Results to date indicate that tonic increases in arterial chemoreceptor afferent input or hypoxia up-regulate NK1R-ir in the cNTS but tonic central chemoreceptor stimulation does not.
Citation InformationKatherine Wilkinson, J. A. Carr, Z. Fu and F. L. Powell. "NK1R expression in the caudal Nucleus of the Solitary Tract (cNTS) during chronic hypoxia and chronic hypercapnia in the rat" FASEB Journal Vol. 21 (2007)
Available at: http://works.bepress.com/katherine_wilkinson/14/