Prenatal nicotine exposure alters respiratory long-term facilitation in neonatal rats

• Published in: Respiratory physiology & neurobiology 2009-12, Vol.169 (3), p.333-337
• Main Authors: Fuller, D.D, Dougherty, B.J, Sandhu, M.S, Doperalski, N.J, Reynolds, C.R, Hayward, L.F
• Format: Article
• Language: English
• Subjects: Age Factors; Analysis of Variance; Animals; Animals, Newborn; Body Weight - drug effects; Developmental plasticity; Female; Hypoxia; Hypoxia - physiopathology; Male; Medical Education; Neonatal; Nicotine; Nicotine - blood; Nicotine - pharmacology; Nicotinic Agonists - blood; Nicotinic Agonists - pharmacology; Plethysmography, Whole Body - methods; Pregnancy; Prenatal; Pulmonary Ventilation - drug effects; Pulmonary/Respiratory; Rats; Rats, Sprague-Dawley; Respiratory Mechanics - drug effects; Respiratory System - drug effects; Ventilation
• ISSN: 1569-9048; 1878-1519
• DOI: 10.1016/j.resp.2009.09.015

Abstract Intermittent hypoxia can evoke persistent increases in ventilation ( V ˙ E ) in neonates ( i.e. long-term facilitation, LTF) (Julien et al., 2008). Since prenatal nicotine (PN) exposure alters neonatal respiratory control (Fregosi and Pilarski, 2008), we hypothesized that PN would influence LTF of ventilation ( V ˙ E ) in neonatal rats. An osmotic minipump delivered nicotine 6 mg/kg per day or saline to pregnant dams. V ˙ E was assessed in unanesthetized pups via whole body plethysmography at post-natal (P) days 9–11 or 15–17 during baseline (BL, 21% O2 ), hypoxia (10 × 5 min, 5% O2 ) and 30 min post-hypoxia. PN pups had reduced BL V ˙ E ( p < 0.05) but greater increases in V ˙ E during hypoxia ( p < 0.05). Post-hypoxia V ˙ E ( i.e. LTF) showed an age × treatment interaction ( p < 0.01) with similar values at P9–11 but enhanced LTF in saline (30 ± 8%BL) vs. PN pups (6 ± 5%BL; p = 0.01) at P15–17. We conclude that the post-natal developmental time course of hypoxia-induced LTF is influenced by PN.