Effect of lesions in the nucleus tractus solitarius (NTS) on hypercapnic ventilatory response (HCVR) in awake ratsFASEB Journal (2006)
AbstractTo test the physiological significance of CO2-sensitive neurons identified in the NTS, we measured the HCVR using barometric pressure plethysmography on unrestrained rats breathing 0, 5 and 7% CO2 in 21% O2 after bilateral NTS lesions with microinjection (200 nL) of substance P-saporin conjugates (SP-SAP, n = 15). For controls we microinjected a conjugate of saporin and an 11 amino acid nonsense peptide (blank, n = 9). Because chronic hypoxia also affects CO2-sensitivy, we studied rats acclimatized to PIO2 = 70 Torr for 7 days (CH; SP-SAP n = 10; blank n = 7). ANOVA showed significant effects of SP-SAP, CH and inspired CO2 on ventilation, with a significant interaction between SP-SAP and inspired CO2. SP-SAP decreased the HCVR mainly by an effect on tidal volume, as previously reported for SP-saporin lesions in the retrotrapezoid nucleus (J. Physiol. 544:603–616, 2002). Immunohistochemistry for the Neurokinin-1 receptor is being used to identify the nature and extent of SP-SAP lesions. Results show a physiological role for chemoreceptors in the NTS but more experiments are necessary to decide if chemoreceptors in the NTS versus other sites play a unique role in ventilatory acclimatization to hypoxia.
Citation InformationKatherine Wilkinson, Z. Fu and F. L. Powell. "Effect of lesions in the nucleus tractus solitarius (NTS) on hypercapnic ventilatory response (HCVR) in awake rats" FASEB Journal Vol. 20 Iss. 4 (2006)
Available at: http://works.bepress.com/katherine_wilkinson/15/