Neuroplasticity of the central hypercapnic ventilatory response: teratogen-induced impairment and subsequent recovery during development.
Neuroventilation is highly plastic and exposure to either of two distinct teratogens, nicotine or ethanol, during development results in a similar loss of the neuroventilatory response to hypercapnia in bullfrog tadpoles. Whether this functional deficit is permanent or transient following nicotine or ethanol exposure was unknown. Here, we tested the persistence of hypercapnic neuroventilatory response impairments in tadpoles exposed to either 30 microg/L nicotine or 0.12-0.06 g/dL ethanol for 10 weeks. Brainstem breathing-related neural activity was assessed in tadpoles allowed to develop teratogen-free after either nicotine or ethanol exposure. Nicotine-exposed animals responded normally to hypercapnia after a 3-week teratogen-free period but the hypercapnic response in ethanol-exposed tadpoles remained impaired. Tadpoles allowed to develop for only 1 week nicotine free after chronic exposure were unable to respond to hypercapnia. The hypercapnic response of ethanol-exposed tadpoles returned by 6 weeks following chronic ethanol exposure. These findings suggest that some nicotine- and ethanol-induced impairments can be resolved during early development. Understanding both the disruptive effects of nicotine and ethanol exposure and how impaired responses return when teratogen exposure stops may offer insight on the function and plasticity of respiratory control.
Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska.
Cord M
CM
Brundage
Barbara E
BE
Taylor
D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000254:growth & development*; D002492:Central Nervous System Depressants / Q000633:toxicity; D000431:Ethanol / Q000633:toxicity; D006935:Hypercapnia / Q000503:physiopathology*; D007814:Larva; D009415:Nerve Net / Q000187:drug effects / Q000254:growth & development; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009538:Nicotine / Q000633:toxicity; D018722:Nicotinic Agonists / Q000633:toxicity; D011892:Rana catesbeiana; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology; D012125:Respiratory Center / Q000187:drug effects / Q000254:growth & development*; D012143:Respiratory Physiological Phenomena / Q000187:drug effects; D013723:Teratogens / Q000494:pharmacology*; D013995:Time
D002492:Central Nervous System Depressants; D018722:Nicotinic Agonists; D013723:Teratogens; D000431:Ethanol; D009538:Nicotine