title: Prenatal exposure to carbon monoxide temporarily impairs maturation of rat cardiomyocytes: Electrophysiological evidence.
abstract: BACKGROUND
  Maternal smoking is an independent risk factor for sudden infant death syndrome. Carbon monoxide (CO) is a major component of cigarette smoke. No information is available concerning the effect of CO and/or smoking on postnatal maturation of the heart.
  
  
  OBJECTIVE
  To investigate the effect of prenatal exposure to CO on cellular electrophysiological maturation in male Wistar rats.
  
  
  METHODS
  The patch-clamp technique was used to measure the action potential and ionic currents (transient outward current and long-lasting type Ca(2+) current) from rat ventricular myocytes.
  
  
  RESULTS
  During growth, action potential duration (APD) measurements at -20 mV and -50 mV (APD(-20) and APD(-50)) progressively decreased in both groups. APD was significantly delayed in rats prenatally exposed to 150 parts per million CO: at four weeks APD(-20) and APD(-50) were 90 ms and 148 ms, respectively, in CO-exposed rats (n=13), and 36 ms and 78 ms, respectively, in control rats (n=14; P<0.01 and P<0.05, respectively); this normalized at eight weeks. After four weeks, the density of long-lasting type Ca(2+) current increased by 34% and the density of transient outward current decreased by 37% in CO-exposed versus control rats; this normalized at eight weeks.
  
  
  CONCLUSIONS
  Prenatal CO exposure affects the physiological shortening of APD in neonatal rats. It is speculated that prolonged myocyte repolarization induced by prenatal exposure to smoke may establish a period of vulnerability for life-threatening arrhythmias during infancy.
authors.affiliation: Center of Molecular Medicine, Department of Pharmacology, University of Florence, Florence;
authors.forename: Laura
authors.initials: L
authors.lastname: Sartiani
authors.forename: Francesca
authors.initials: F
authors.lastname: Stillitano
authors.forename: Simona
authors.initials: S
authors.lastname: Brogioni
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cuomo
authors.forename: Maria R
authors.initials: MR
authors.lastname: Carratù
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mugelli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Cerbai