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Neural mechanisms and delayed gastric emptying of liquid induced through acute myocardial infarction in rats.

Nunez WR, Ozaki MR, Vinagre AM, Collares EF, Almeida EA - Arq. Bras. Cardiol. (2014)

Bottom Line: Intravenous prazosin was used to produce chemical sympathectomy.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.

View Article: PubMed Central - PubMed

Affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.

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.

Conclusion: Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN.

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Related in: MedlinePlus

Results of gastric retention (%) in groups of rats with myocardial infarction andlesions of the paraventricular nucleus * p < 0.05.
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f04: Results of gastric retention (%) in groups of rats with myocardial infarction andlesions of the paraventricular nucleus * p < 0.05.

Mentions: Figure 4 shows the results of the lesion seen inthe paraventricular nucleus in a prior study. Rats with electrolytic PVN lesion andinfarction showed a significantly lower GR% (PVNX + INF = 25.0 ± 3.0%, N = 8) comparedto animals with sham lesion (PVNS) and infarction (PVNS+INF = 41,2 ±1,7%,N=8). The samelesion did not reduce GR% in control animals (PVNX + SH = 28.5 ± 2.9%, N = 8 vs. PVNS +SH = 32.1 ± 1.9%, N = 10). The infarcted area of the left ventricle, in mean ± SEM, inPVNS + INF animals was 52.2 ± 0.4% and 55.4 ± 0.8% in PVNX + INF animals. As for thehistological assessment of the brains after the PVN lesion, only lesions involving 100%of the paraventricular region were considered for this study.


Neural mechanisms and delayed gastric emptying of liquid induced through acute myocardial infarction in rats.

Nunez WR, Ozaki MR, Vinagre AM, Collares EF, Almeida EA - Arq. Bras. Cardiol. (2014)

Results of gastric retention (%) in groups of rats with myocardial infarction andlesions of the paraventricular nucleus * p < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4375658&req=5

f04: Results of gastric retention (%) in groups of rats with myocardial infarction andlesions of the paraventricular nucleus * p < 0.05.
Mentions: Figure 4 shows the results of the lesion seen inthe paraventricular nucleus in a prior study. Rats with electrolytic PVN lesion andinfarction showed a significantly lower GR% (PVNX + INF = 25.0 ± 3.0%, N = 8) comparedto animals with sham lesion (PVNS) and infarction (PVNS+INF = 41,2 ±1,7%,N=8). The samelesion did not reduce GR% in control animals (PVNX + SH = 28.5 ± 2.9%, N = 8 vs. PVNS +SH = 32.1 ± 1.9%, N = 10). The infarcted area of the left ventricle, in mean ± SEM, inPVNS + INF animals was 52.2 ± 0.4% and 55.4 ± 0.8% in PVNX + INF animals. As for thehistological assessment of the brains after the PVN lesion, only lesions involving 100%of the paraventricular region were considered for this study.

Bottom Line: Intravenous prazosin was used to produce chemical sympathectomy.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.

View Article: PubMed Central - PubMed

Affiliation: Universidade Estadual de Campinas, Campinas, SP, Brasil.

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.

Conclusion: Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN.

Show MeSH
Related in: MedlinePlus