Pre‐ and early postnatal nicotine exposure exacerbates autoresuscitation failure in serotonin‐deficient rat neonates

Abstract

Cigarette smoking during pregnancy increases the risk of sudden infant death syndrome (SIDS), and nicotine replacements, a key ingredient of cigarettes, have been recently prescribed to women who wish to quit smoking during their pregnancy. Serotonin (5-HT) abnormalities have been consistently identified in many SIDS cases. Here we investigated the effects of perinatal nicotine exposure in mild 5-HT deficiency rat neonates on autoresuscitation, a protective cardiorespiratory reflex. The mild 5-HT deficiency was induced by a maternal tryptophan-deficient diet, and nicotine was delivered from embryonic day (E) 4 to postnatal day (P) 10 at 6 mg kg day through an osmotic pump. In P10 rats, nicotine exposure exacerbates autoresuscitation failure (mortality) in mildly 5-HT-deficient rats to a greater extent than in controls (P = 0.029). The recovery of eupnoea and heart rate to baseline values following repetitive anoxic events (which elicit an apnoea accompanied by a bradycardia) is significantly delayed in 5-HT-deficient rats treated with nicotine, making them more susceptible to failure of autoresuscitation (eupnoea recovery: P = 0.0053; heart rate recovery: P = < 0.0001). Neither 5-HT deficiency nor nicotine exposure alone appears to affect the ability to autoresuscitate significantly when compared among the four treatments. The increased vulnerability to environmental stressors, e.g. severe hypoxia, asphyxia, or anoxia, in these nicotine-exposed 5-HT-deficient neonates during postnatal developmental period is evident.

Obstetricians’ and Gynecologists’ Communication Practices around Smoking Cessation in Pregnancy, Secondhand Smoke and Sudden Infant Death Syndrome (SIDS): A Survey

“…Although the effects of electronic nicotine delivery systems (ENDS) aerosol exposure on SIDS in humans are unknown, there is animal and epidemiological evidence that nicotine exposure (as found in ENDS aerosol), both pre and postnatally, could impact the risk of SIDS [4,39,40]. Emissions from ENDS are not benign, especially in indoor locations, and could present potential health hazards to bystanders, such as infants.…”

The Role of Maternal Smoking in Sudden Fetal and Infant Death Pathogenesis

“…In the CNS, nicotine exposure has been shown to lead to neuronal hypoplasia, as well as an inappropriate early terminal differentiation of developing neurons, which is reflected in greater levels of expression of the post-mitotic cellular marker, neuronal nuclear antigen, in smoke-exposed victims (13,53). Additionally, abnormal levels of neurotransmitters have been shown and abnormal neuronal function due to nicotine exposure (54,55). These findings can be observed throughout the central nervous system, including the brainstem, cerebellar cortex, and spinal cord, but also in peripheral organ systems (45,56).…”

Everything you wanted to know about e-cigarettes and vaping but were afraid to ask: a guide for mental health clinicians

“…What was less widely reported was that this link was based on laboratory experiments in which unborn rats were exposed to nicotine in order to study serotonin levels. Rats that had been exposed to nicotine and were born with a serotonin deficiency had a poorer ability to respond to and recover from oxygen deprivation than those that were either exposed to nicotine and born with normal serotonin or that had a serotonin deficiency but were not exposed to nicotine (Lee 2018).…”