ABSTRACT
AIMS: We previously reported that mechanical atrial stretch (AS) by balloon distention increased gastric tonus in anesthetized rats. The present study evaluated the effect of AS on the gastric emptying of a liquid test meal in awake rats and its underlying neural mechanisms. MAIN METHODS: Anesthetized male rats received a balloon catheter into the right atrium and a gastrostomy cannula. The next day, mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), and cardiac output (CO) were continuously monitored. After the first 20min of monitoring (basal interval), the balloon was either distended or not (control) with 30, 50, or 70µl saline for 5min. Fifteen minutes later, the rats received the test meal (glucose solution with phenol red), and fractional gastric dye retention was determined 10, 20, or 30min later. KEY FINDINGS: Heart rate and CVP values were transiently increased by 50 or 70µl AS but not 30µl AS, whereas gastric emptying was slower after 30, 50, or 70µl AS than after sham distention. Subdiaphragmatic vagotomy or splanchnicotomy+celiac ganglionectomy and capsaicin, ondansetron, hexamethonium, L-NAME, and glibenclamide treatment prevented the AS-induced delay in gastric emptying, whereas atropine and guanethidine treatment failed to prevent it. SIGNIFICANCE: Atrial stretch inhibited the gastric emptying of liquid via non-adrenergic and non-cholinergic pathways that activate nitric oxide-K(+)ATP channels.
Subject(s)
Atrial Function, Right/physiology , Gastric Emptying/physiology , Gastrointestinal Transit/physiology , Heart Atria/surgery , Hypovolemia/physiopathology , Analysis of Variance , Animals , Atropine/pharmacology , Balloon Occlusion/methods , Blood Pressure , Capsaicin/pharmacology , Cardiac Catheterization/methods , Catheterization/methods , Gastric Emptying/drug effects , Gastrostomy/methods , Glyburide/pharmacology , Guanethidine/pharmacology , Heart Rate , Hexamethonium/pharmacology , Male , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide/blood , Ondansetron/pharmacology , RatsABSTRACT
Durante uma investigación de 21 pacientes consecutivos portadores de artrite reumatóide clássica (AR), foram encontradas anormalidades na funçäo pulmonar atribuíveis à AR em 52,4%, tendo a reduçäo da capacidade de difusäo e da queda da PaO2 após exercício sido as anormalidades mais comuns. Outras alteraçöes encontradas foram o shunt patológico, distúrbio espirográfico restritivo e hipoxemia em repouso. Os sintomas atribuíveis à AR foram infreqüentes, assim como as alteraçöes radiológicas. Em um caso, ocorreu alteraçäo radiológica com funçäo pulmonar normal. Desses 21 pacientes, seis estavam em tratamento com sais de ouro, droga esta que vem sendo descrita na literatura como capaz de desencadear doença intersticial pulmonar. No grupo estudado, näo houve correlaçäo entre a presença de deformidades e/ou erosäo óssea ou de títulos sorológicos elevados como alteraçöes pulmonares atribuíveis à AR
