Effect of graded doses of methysergide on basal and pentagastrin stimulated gastric secretion in anaesthetised rats.

The effect of continuous infusion (iv) of graded doses of methysergide (0.1-50 microgram(s)/kg/hr) was studied on basal and pentagastrin (5 microgram(s)/kg/hr) stimulated gastric acid secretion in anaesthetised rats by the slow, continuous stomach perfusion method. Both basal and pentagastrin stimulated acid secretion indicated a biphasic response. Methysergide induced stimulation at a lower dose of 1 microgram(s)/kg/hr and inhibition at higher doses of 20-50 microgram(s)/kg/hr. The stimulatory effect may be due to postsynaptic receptor blockade while the inhibitory effect at higher dose may be due to blockade of presynaptic 5-HT autoreceptors, or due to a direct inhibitory effect of unknown basis.

effect of gastric secretagogues during ontogenesis in rats

The effects of histamine, bethanechol and pentagastrin on gastric acid secretion were studied in rats of younger and older age groups. After 48 hours starvation, the pylorus was ligated and each of the secretagogues was administered subcutaneously to individual groups. Four hours later the animals were sacrified by chloroform-induced asphyxia and the stomach was removed after ligating the cardiac end. The stomach contents, obtained by flushing with 3 ml of distilled water, were used to determine the volume of gastric juice and its free and total acidity. Histamine and bethanechol produced a greater increase in the volume and acidity of gastric juice in older animals as compared to younger ones. Pentagastrin also produced greater increase in these parameters in older animals but it was not statistically significant. Possible explanation of these results include variable size of parietal cell mass and/or difference in the sensitivity of parietal cells to individual secretagogues in animals of different age groups

Effect of pentagastrin on gastric bicarbonate secretion in patients with duodenal ulcer & healthy controls.

We studied the gastric acid and bicarbonate secretion rates in 12 patients with duodenal ulcer and 6 age matched healthy controls. Measurements of gastric juice volume (nonparietal and parietal), acidity and osmolality were done. The ulcer patients secreted more acid, parietal and nonparietal fluid than controls under basal conditions and after subcutaneous pentagastrin injection (6 micrograms/kg body weight). However, the gastric bicarbonate secretion was similar in the duodenal ulcer patients and controls, both under basal state as well as after pentagastrin stimulation. The gastric acidity was similar in ulcer patients and control subjects under both the states (49.3 +2- 4.5 vs 50.0 +/- 6.0 mmol/l basally, 85.2 +/- 8.9 vs 63.4 +/- 6.6 mmol/l after pentagastrin injection respectively). Thus, gastric bicarbonate secretion was similar, whereas parietal and nonparietal volume secretions were increased in patients with duodenal ulcer as compared to controls.

Gastric acid secretion response in the Cebus apella: a monkey model of chronic Chagas' disease

The objective was to study the secretory pattern, both basal and stimulated either by histamine (0.1 mg/kg) or pentagastrin (64 micrograms/kg) in eighteen Cebus apella monkeys chronically infected with different T. cruzi strains (CA1, n = 10; Colombian, n = 4 and Tulahuen, n = 4) and to describe the morphological findings in the gastrointestinal tract in twelve infected (6 sacrificed and 6 spontaneously dead) and four healthy monkeys. All infected monkeys and 35 healthy ones were evaluated by contrast X-ray examination. No differences were observed in basal acid output between control and infected groups. Animals infected with the Tulahuen and Colombian strains showed significant lower values of peak acid output in response to histamine or pentagastrin (p < 0.01 and p < 0.05 respectively; t test) in comparison to the controls. Barium contrast studies showed enlargement and dilatation of the colon in three infected animals. Histopathological lesions were seen in 75% of the autopsied animals either in colon alone (33%) or both, in colon and esophagus (42%). The normal secretion observed in the CA1 infected group could be due to a lower virulence of the strain, a lower esophageal tropism or the necessity of a longer post-infection time to cause lesions

Response of the lower esophageal sphincter to pentagastrin on patients with megaesophagus secondary to Chagas' disease

Em 12 pacientes com megaesôfago chagásico e 12 controles, a pressäo do esfincter inferior do esôfago foi determinada pelo método manomético em condiçöes basais e após infusäo i.v. de pentagastrina nas foses de 0,5, 1,0, 2,0 e 4,0 ug/Kg/h. A pressäo basal média (36,2 ñ 2,5 cm H2O) foi significativamente mais alta (p < 0,05) no grupo de megaesôfago do que no grupo de controle (27,4 ñ 1,8 cm H2O). Durante a infusäo de pentagastrina, os valores da pressäo do enfincter esogagiano inferior foram significativamente mais altos (p < 0,05) no grupo de doença de Chagas. O nível mais alto foi atingido com a dose de 0,5 ug/Kg/h no grupo controle e com 1,0 ug/Kg/h no grupo chagásico (p < 0,05). Os pacientes com megaesôfago necessitaram de doses maiores de epntagastrina para alcançar a contraçäo máxima

Efeito de estímulos fisiológicos sobre a motricidade do esfíncter de Oddi / Effect of physiological stimuli on the Oddi's sphincter motility

A atividade mioelétrica do esfíncter de Oddi foi avaliada tanto nos estados de jejum, como prandial e após a administraçäo de hormônios gastrointestinais que podem desempenhar uma importante funçäo no controle da motricidade do esfíncter de Oddi. A eletromiografia do esfíncter de Oddi e do trato gastrointestinal foi realizada em 21 opossums em jejum e após a administraçäo de 20 Cal/kg de lipídios, proteínas, carboidratos ou de uma mistura isocalórica desses três alimentos. O efeito de hormônios gastrointestinais (colecistoquinina, gastrina, glucagon e secretina) também foi estudado. O segmento proximal do esfíncter de Oddi gerou potenciais de açäo espontâneos que se propagaram para o segmento distal do esfíncter. O esfíncter de Oddi apresenta uma variaçäo na freqüência dos potenciais de açäo durante o jejum que se correlaciona com a atividade mioelétrica do trato gastrointestinal, denominada complexo mioelétrico migratório. Após a administraçäo de alimentos, o complexo mioelétrico migratório foi abolido e substituído por um outro de atividade mioelétrica prandial, cuja duraçäo e freqüência dos potenciais de açäo dependiam do tipo de alimento. A colecistoquinina e a pentagastrina aumentaram e o glucagon e a secretina diminuiram a freqüência dos potenciais de açäo no esfíncter de Oddi. Conclui-se que o esfíncter de Oddi pode desempenhar a funçäo importante de propelir e coordenar o tempo e o volume de drenagem para o duodeno

Açäo da pentagastrina no esfíncter inferior do esôfago de pacientes com megaesôfago chagásico / Effect of pentagastrin on the lower esophageal sphincter in patients with chagasic megaesophagus

Com o objetivo de estudar o comportamento do esfíncter inferior do esôfago (E.I.E.) em pacientes com doenças de Chagas, foram analisados os valores da pressäo esfincteriana basal e o padräo de resposta do esfíncter a doses crescentes de Pentagastrina (PG) administrada em infusäo I.V. constante. Os resultados de pacientes com a Forma Indeterminada (12 casos) e com Megaesôfago chagásico (12 casos) foram comparados aos obtidos em um Grupo Controle (12 casos). Para a análise do comportamento do E.I.E. foi empregado o método manométrico com tubos abertos e infusäo constante de água (1,6 cm*3/min). O registro das pressöes intraluminares foi realizado através do sistema de retirada rápida. Inicialmente era administrada soluçäo fisiológica e, a seguir, PG nas doses de 0,5-1,0-2,0-4,0 microng/Kg/h, respectivamente, diluída em água destilada equivalendo a um volume de 20 cm*3/h. Cada uma das soluçöes era infundida por aproximadamente 15 minutos, intercaladas com a administraçäo de soluçäo fisiológica. Os seguintes resultados (média aritmética, x, ñ erro padräo da média, e.p.m.), expressos em cm H20, foram obtidos: 1) durante a infusäo de soro fisiológico I.V., a pressäo do E.I.E. apresentou valores médios de 27,4ñ1,8 no Grupo Controle; 33,0+2,3 no grupo portador de Forma Indeterminada e 36,2ñ2,5 no Grupo Megaesôfago; 2) durante a infusäo de PG, a pressäo ao nível do E.I.E. apresentou os seguintes valores, respectivamente, para as doses de 0,5-1,0-2,0-4,0 microng/kg/h: 37,7ñ3,0; 40,5ñ2,9ñ40,4ñ3,3; 43,