title: Possible role of afferent autonomic signals in abdominal organs in anorexic and cardiovascular responses to nicotine injection in rats.
abstract: Smoking generally causes an increase in nicotine levels in the blood, affecting the brain components, such as the hypothalamus (feeding-related area) or the brain stem (cardiovascular control area). In terms of nicotine transmission to the brain, a new insight that the afferent vagal nerve in the liver is important for sensing increased nicotine levels in the blood and informing the brain was reported in an experiment with rats. However, it has not been clarified whether the afferent autonomic nerve system is implicated in feeding and cardiovascular responses to nicotine. Here, we examined the possible role of afferent autonomic nerve transmission in rats in regulating feeding behavior and cardiovascular functions by nicotine. An intravenous injection of nicotine dose dependently increased the blood pressure (BP) in urethane-anesthetized rats; high nicotine doses also led to an increase in BP in conscious rats. Further, an intravenous injection of nicotine for 3 days reduced food intake and body weight gain in rats. The weight-reducing action of intravenous nicotine was abolished by blocking the afferent sympathetic signals in the abdominal organs, but not the vagal nerve signals. Moreover, the hypertensive action of nicotine was not abolished either by afferent sympathectomy or by vagotomy. Thus, these data suggest that nicotine injected into the vein acts on the afferent sympathetic nerve in the abdominal organs and transmits signals to the brain for reducing body weight, but not for suppressing appetite or increasing BP.
authors: aDepartment of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga bDepartment of Physiology II, Kanazawa Medical University, Uchinada, Ishikawa, Japan.
authors: Shintaro
authors: S
authors: Yagi
authors: Mamoru
authors: M
authors: Tanida
authors: Jun
authors: J
authors: Satomi
mesh_terms: D000818:Animals; D000855:Anorexia / Q000139:chemically induced* / Q000503:physiopathology*; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009538:Nicotine / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D013562:Sympathectomy; D014628:Vagotomy; D015431:Weight Loss / Q000187:drug effects
chemical_list: D009538:Nicotine