Analysis of a novel functional polymorphism within the promoter region of the serotonin transporter gene (5-HTT) in Brazilian patients affected by bipolar disorder and schizophrenia.

It has been suggested that the serotonin transporter (5-hydroxytryptamine-transporter or 5-HTT) may be involved in the pathogenesis of affective disorders. Recently, Collier et al. (1996) found that the frequency of the low-activity short variant (s) of the 5-HTT-linked polymorphic region (5-HTTLPR) was higher among patients with affective disorders than in normal controls. However, since the observed level of significance was not high, they suggest that these findings should be replicated in independent samples. We have analyzed 86 unrelated patients (47 with bipolar disorder and 39 with schizophrenia) and 98 normal controls from the Brazilian population for the 5-HTTLPR. Statistical analysis revealed that the genotypes (LL, Ls, ss) as well as the estimated allele frequencies (L,s) did not differ significantly among the three studied groups or between bipolar and normal controls. In addition, although not statistically significant, the genotype ss in our sample was less frequent among our bipolar patients than in our normal controls (12.8% versus 16.3%) which is the opposite of what was found by Collier et al. (24% versus 18%) in the European study. Although it will be important to extend the present analysis in a larger sample, our preliminary results suggest that the 5-HTTLPR does not seem to play a major role in the genetics of bipolar and schizophrenic disorders at least in this group of Brazilian psychiatric patients.

Dose-related inhibition of gastric secretion by intraduodenal trypsinogen in dogs.

It has been shown previously that trypsinogen and its activation peptide but not trypsin decreased gastric secretion. The purpose of this work was to study the dose-action relation between the intraduodenal infusion of trypsinogen and gastric secretion. Three dogs provided with gastric and duodenal Thomas fistulae were stimulated by continuous i.v. perfusion of porcine gastrin I-II (6 microgram kg-1 h-1). Pancreatic juice was diverted to the exterior and gastric secretion was collected. Upon reaching a gastric secretory plateau, porcine trypsinogen was infused intraduodenally at doses of 5, 10, 20, 40, 80 and 160 mg. Each test was continued for a further 60 min. Control was made with isotonic saline. There was a dose-related inhibition of the gastrin-stimulated gastric acid output. This inhibition reached a maximum of 50% with 40 mg of intraduodenal trypsinogen, showing no increase with higher doses.

[Pancreatic dose-response curves to cholecystokinin in dogs (author's transl)]. / Vergleich zweier Methoden zur Bestimmung der Dosis-Wirkungsbeziehung zwischen Cholezystokinin und exokriner Pankreassekretion beim Hund.

Dose-response (DR) curves for pancreatic flow rate, bicarbonate and protein output to cholecystokinin (CCK) were determined by two techniques in 3 conscious dogs with gastric and duodenal Thomas fistulas. With the continuous DR technique the dose of CCK was doubled each 45 minutes and with the single DR technique, only one dose of CCK was infused on each test day. The dose-response curves for pancreatic flow rate and bicarbonate output did not differ with the two techniques. The maximal protein output was higher with the single DR than with the continuous DR technique.

Canine exocrine pancreatic secretory changes induced by an intragastric ethanol test meal.

In five dogs with chronic gastric fistulas (Thomas cannula) and a new type of chronic pancreatic fistula which permits collection of pure nonactivated pancreatic juice after ingestion of a test meal, the following series of experiments were performed: In the first series, a test meal (400 gm. canned dog meat) was given with 200 ml. saline simultaneously infused through the gastric cannula. In response to this stimulus, the 20-minute peak pancreatic flow rate and bicarbonate output were respectively 33% and 34%, of the maximal secretion of the pancreatic gland obtained with secretin in six control dogs provided with gastric and the classical Thomas duodenal fistula. The 20-minute peak protein output represented 84% of the maximal secretory capacity attained with dose-response curves to CCK in the same group of control animals. In the second series either 1.5 or 2.0 gm./kg. ethanol were given instead of saline. Intragastric ethanol induced a dissociation of pancreatic secretion: a significant inhibition of flow rate, of bicarbonate concentration and output and a significant rise of protein concentration; protein output remaining unchanged. It is postulated that ethanol, acting on the stomach and duodenojejunum, evokes, independently of its gastrin-releasing capacity, and unknown humoral or nervous mechanism that counteracts the ethanol-elicited cholinergic-mediated inhibition of pancreatic protein secretion which has been previously described.

Evidences for duodenopancreatic reflexes and an anti-CCK factor with lidocaine infused intravenously and sprayed topically on pancreatic papilla in nonalcoholic and alcohol-fed dogs.

In 14 duodenal Thomas fistula dogs, four of them alcohol-fed for two years, lidocaine, applied topically to the duodenal pancreatic papilla, inhibited secretin-induced pancreatic secretion probably by interrupting duodenopancreatic reflexes that contribute to the "pancreon's" cholinergic tone. Opposite effects were observed with lidocaine administered against a CCK plus secretin background stimulation of the pancreas. The significant rising of volume and protein output above plateau levels were enhanced by chronic alcohol feeding. Lidocaine infused intravenously did not change secretin-induced pancreatic secretion but raised CCK and secretin evoked plateau secretion levels. Chronic alcoholism enhanced these latter effects. Atropine perfusion superimposed on CCK and secretin stimulation did not prevent but raised the intravenous lidocaine-induced pancreatic secretion changes. It is postulated that the modifications elicited by lidocaine sprayed topically and infused intravenously on CCK plus secretin evoked pancreatic secretion plateau levels are due to depression of an anti-CCK factor secreted by the small intestine mucosa.