title: Neural mechanisms and delayed gastric emptying of liquid induced through acute myocardial infarction in rats.
abstract: BACKGROUND
  In pathological situations, such as acute myocardial infarction, disorders of motility of the proximal gut can trigger symptoms like nausea and vomiting. Acute myocardial infarction delays gastric emptying (GE) of liquid in rats.
  
  
  OBJECTIVE
  Investigate the involvement of the vagus nerve, α 1-adrenoceptors, central nervous system GABAB receptors and also participation of paraventricular nucleus (PVN) of the hypothalamus in GE and gastric compliance (GC) in infarcted rats.
  
  
  METHODS
  Wistar rats, N = 8-15 in each group, were divided as INF group and sham (SH) group and subdivided. The infarction was performed through ligation of the left anterior descending coronary artery. GC was estimated with pressure-volume curves. Vagotomy was performed by sectioning the dorsal and ventral branches. To verify the action of GABAB receptors, baclofen was injected via icv (intracerebroventricular). Intravenous prazosin was used to produce chemical sympathectomy. The lesion in the PVN of the hypothalamus was performed using a 1 mA/10 s electrical current and GE was determined by measuring the percentage of gastric retention (% GR) of a saline meal.
  
  
  RESULTS
  No significant differences were observed regarding GC between groups; vagotomy significantly reduced % GR in INF group; icv treatment with baclofen significantly reduced %GR. GABAB receptors were not conclusively involved in delaying GE; intravenous treatment with prazosin significantly reduced GR% in INF group. PVN lesion abolished the effect of myocardial infarction on GE.
  
  
  CONCLUSIONS
  Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN.
authors.affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: Wilson Ranu Ramirez
authors.initials: WR
authors.lastname: Nunez
authors.affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: Michiko Regina
authors.initials: MR
authors.lastname: Ozaki
authors.affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: Adriana Mendes
authors.initials: AM
authors.lastname: Vinagre
authors.affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: Edgard Ferro
authors.initials: EF
authors.lastname: Collares
authors.affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: Eros Antonio de
authors.initials: EA
authors.lastname: Almeida
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D058786:GABA-B Receptor Agonists / Q000494:pharmacology; D005746:Gastric Emptying / Q000502:physiology*; D018589:Gastroparesis / Q000503:physiopathology; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology*; D010286:Paraventricular Hypothalamic Nucleus / Q000503:physiopathology*; D011224:Prazosin / Q000494:pharmacology; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D018080:Receptors, GABA-B / Q000502:physiology*; D013997:Time Factors; D014628:Vagotomy; D014630:Vagus Nerve / Q000503:physiopathology*
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D058786:GABA-B Receptor Agonists; D018340:Receptors, Adrenergic, alpha-1; D018080:Receptors, GABA-B; D001418:Baclofen; D011224:Prazosin