Hydrogen sulfide ameliorates prenatal cigarette smoke exposure-induced impairment of respiratory responses to hypercapnia in neonatal rats

Abstract The present study was designed to investigate whether H 2 S could improve the respiratory responses to hypercapnia blunted by prenatal CSE in neonatal rats in vivo. Respiratory activities were recorded with head-out body plethysmography. The results showed that during baseline, respiratory frequency ( F R ), tidal volume ( V T ) and minute ventilation ( V E ) were similar among tested groups; frequency of spontaneous apnea ( F SA ), not post-sigh apnea ( F PA ), was significantly elevated by prenatal CSE. During hypercapnia, the increases in F R and V E were significantly reduced, but V T was not markedly different, in CSE group; both F SA and F PA were decreased, although F SA remained higher in CSE group. All the aforementioned effects induced by CSE on respiratory activities were relieved by NaHS (donor of H 2 S, 56 μmol/kg by intraperitoneal injection). These data indicate that H 2 S could ameliorate the disruption of respiratory responses to hypercapnia induced by prenatal CSE in neonatal rats.