Ventral medulla pHi measured in vivo by 31P NMR is not regulated during hypercapnia in anesthetized rat.

摘要: Chemoreceptors in the ventral medulla contribute to respiratory response hypercapnia. Do they ‘sense’ intracellular pH (pHi)? We measured pHi or cortex (control) using 31P-NMR obtained via a novel 3×5 mm2 surface coil anesthetized rats breathing air 7% CO2. During over 240 min, decreased slightly from 7.13±0.02 7.05±0.02 (SEM; n=5; 2 cortex, 3 medulla). 180 min of hypercapnia, cortical (n=4) 7.17±0.02 6.87±0.01 by 90 and recovered 150 min. Ventral showed no such regulation. It 7.11±0.02 6.88±0.02 at only after cessation hypercapnia (n=5), results consistent with being chemoreceptor stimulus. However, non-chemoreceptor neurons that our medullary NMR signal also do not appear regulate vitro. Regional differences regulation between may be due both chemosensitive non-chemosensitive neurons.