Peer-Reviewed Journal Details
Mandatory Fields
McDonald, FB;Chandrasekharan, K;Wilson, RJA;Hasan, SU
2016
December
American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Interactive effects of maternal cigarette smoke, heat stress, hypoxia, and lipopolysaccharide on neonatal cardiorespiratory and cytokine responses
Validated
Optional Fields
SUDDEN-INFANT-DEATH PRENATAL NICOTINE EXPOSURE ENVIRONMENTAL TOBACCO-SMOKE INTERMITTENT HYPOXIA BRAIN-STEM RAT PUPS THERMAL ENVIRONMENT BREATHING PATTERN PRETERM INFANTS NEWBORN RATS
311
1113
1124
Maternal cigarette smoke (CS) exposure exhibits a strong epidemiological association with Sudden Infant Death Syndrome, but other environmental stressors, including infection, hyperthermia, and hypoxia, have also been postulated as important risk factors. This study examines whether maternal CS exposure causes maladaptations within homeostatic control networks by influencing the response to lipopolysaccharide, heat stress, and/or hypoxia in neonatal rats. Pregnant dams were exposed to CS or parallel sham treatments daily for the length of gestation. Offspring were studied at postnatal days 6-8 at ambient temperatures (Ta) of 33 degrees C or 38 degrees C. Within each group, rats were allocated to control, saline, or LPS (200 mu g/kg) treatments. Cardiorespiratory patterns were examined using head-out plethysmography and ECG surface electrodes during nor-moxia and hypoxia (10% O-2). Serum cytokine concentrations were quantified from samples taken at the end of each experiment. Our results suggest maternal CS exposure does not alter minute ventilation (V-E) or heart rate (HR) response to infection or high temperature, but independently increases apnea frequency. CS also primes the inflammatory system to elicit a stronger cytokine response to bacterial insult. High Ta independently depresses V-E but augments the hypoxia-induced increase in V-E. Moreover, higher Ta increases HR during normoxia and hypoxia, and in the presence of an immune challenge, increases HR during normoxia, and reduces the increase normally associated with hypoxia. Thus, while most environmental risk factors increase the burden on the cardiorespiratory system in early life, hyperthermia and infection blunt the normal HR response to hypoxia, and gestational CS independently destabilizes breathing by increasing apneas.
BETHESDA
0363-6119
10.1152/ajpregu.00062.2016
Grant Details