Cardiorespiratory Responses of 5HT-Deficient Pet-1 Knockout Mice to Repetitive Anoxic Challenges Following in Utero Nicotine Exposure

Abstract

We previously tested the effects of developmental nicotine exposure (DNE) on breathing behavior in intact and unanesthetized neonatal wild type (WT) and Pet-1 knockout (KO) mice. Nicotine is a neuroteratogen, a major component of cigarette smoke, and is widely believed to be the causative agent underlying the increased risk for SIDS due to maternal smoking. Surprisingly, we found that DNE resulted in a functional recovery of the breathing deficits that are characteristic of the Pet-1 KO phenotype, but did not decrease neonatal mortality. This led us to consider the effects of DNE on cardiac control since abnormalities in heart rate and/or heart rate variability could result in sudden death. We therefore repeated our autoresuscitation study while measuring breathing and heart rate simultaneously. In addition, we extended this study by exposing saline- and nicotine-treated WT and Pet-1 KO mice to repeated autoresuscitation challenges.