Francisco José Batista-Lima

Inhibitory effects of a standardized extract of Justicia pectoralis in an experimental rat model of airway hyper-responsiveness

Justicia pectoralis is a plant useful for the treatment of respiratory diseases. Here, we studied the antiasthmatic properties of a standardized extract of J. pectoralis (Jp).

Endothelium-independent vasodilator effect of 2-nitro-1-phenyl-1-propanol on mesenteric resistance vessels in rats

Abstract 2‐Nitro‐1‐phenyl‐1‐propanol (NPP) is a nitro alcohol with vasodilator activity in the rat aorta. The present study investigated the vasodilator properties of NPP in small vessels of the mesenteric bed, which, contrary to the aorta, contains resistance vessels. Using myography, isometric contractions were recorded in rings of second‐ and third‐order branches from the rat mesenteric artery. NPP relaxed mesenteric ring preparations that were contracted with phenylephrine, U‐46619, and KCl (40 mM), resulting in significantly different EC50 values (0.41 &mgr;M [0.31–0.55 &mgr;M], 0.16 &mgr;M [0.10–0.24 &mgr;M], and 4.50 &mgr;M [1.86–10.81 &mgr;M], respectively). NPP‐induced vasodilation decreased as the extracellular K+ concentration increased. The pharmacological blockade of K+ channels with tetraethylammonium, BaCl2, CsCl, and apamin also blunted NPP‐induced vasorelaxation. In contrast, NPP‐induced vasodilation was resistant to indomethacin, L‐NG‐nitroarginine methyl ester (L‐NAME), and endothelium removal, indicating that neither prostaglandins nor the endothelial release of nitric oxide is involved in the relaxant effects of NPP. Conversely, 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ), cis‐N‐(2‐phenylcyclopentyl)‐azacyclotridec‐1‐en‐2‐amine hydrochloride (MDL‐12,330 A), and H‐89 reduced NPP‐induced vasodilation. Under Ca2+‐free conditions, NPP did not alter transient contractions that were evoked by caffeine, but it reduced transient contractions that were evoked by phenylephrine. In mesenteric rings that were loaded with the fluorescent Ca2+ indicator Fluo‐4 AM and stimulated with phenylephrine, NPP blunted both contractions and fluorescence signals that were related to cytosolic Ca2+ levels. In conclusion, the vasodilatory actions NPP on mesenteric vessel resistance involved the participation of cyclic nucleotides and the opening of K+ channels.

Extracellular acidosis selectively inhibits pharmacomechanical coupling induced by carbachol in strips of rat gastric fundus

What is the central question of this study? Acute acidosis that results from short‐term exercise is involved in delayed gastric emptying in rats and the lower responsiveness of gastric fundus strips to carbachol. Does extracellular acidosis decrease responsiveness to carbachol in tissues of sedentary rats? How? What is the main finding and its importance? Extracellular acidosis inhibits cholinergic signalling in the rat gastric fundus by selectively influencing the Gq/11 protein signalling pathway.

A simple laboratory exercise with rat isolated esophagus and stomach fundus to reveal functional differences between striated and smooth muscle cells

This study describes an undergraduate student laboratory activity using isolated preparations from rat gastrointestinal tissues that possess contractile profiles typically exhibited by striated and smooth muscle cells. While students are introduced to an ex vivo methodology, they can compare differences in trace experiments, twitch aspects, phasic and tonic properties, force-frequency relationships, and pharmacological responsiveness of esophageal (striated) and fundic (smooth muscle) segments. Muscle strips were subjected to electrical field stimulation (EFS) applied by platinum electrodes immersed in the physiological solution. The contractile profile of EFS responses varied between these two types of gut preparations. Atropine and tubocurarine revealed differential inhibitory influences in esophagus or fundus tissues; caffeine and procaine produced similar effects, i.e., potentiation and blockade of the EFS-induced contractile response in these tissues, respectively. Experimental results obtained during the activity helped the improvement of student learning about basic concepts previously discussed in theoretical lectures. To measure student learning with this laboratory exercise, a questionnaire was applied before and after the activity, and the number of expected correct answers, concerning the mechanisms of contraction in striated and smooth muscle, could be clearly evidenced.

Topical protection of mice laryngeal mucosa using the natural product cashew gum

Evaluate the effect of in vitro exposure of mice laryngeal mucosa to solutions that simulated human gastric juice and to assess the topical protective effect of cashew gum on mice laryngeal mucosal integrity in vitro.

Dual excitatory and smooth muscle‐relaxant effect of β‐phenylethylamine on gastric fundus strips in rats

β‐Phenylethylamine (β‐PEA) is a trace amine with chemical proximity to biogenic amines and amphetamines. It is an endogenous agonist of trace amine‐associated receptors (TAARs) that acts as a neuromodulator of classic neurotransmitters in the central nervous system. At high concentrations, β‐PEA contracts smooth muscle, and a role for TAARs in these responses has been postulated. The high dietary intake of trace amines has been associated with such symptoms as hypertension and migraine, especially after the intake of foods containing such compounds. In gastrointestinal tissues, TAAR expression was reported, although the effect of β‐PEA on gastric contractile behaviour is unknown. Here, isolated strips that were obtained from the rat gastric fundus were stimulated with high micromolar concentrations of β‐PEA. Under resting tonus, β‐PEA induced contractions. In contrast, when the strips were previously contracted with KCl, a relaxant response to β‐PEA was observed. The contractile effect of β‐PEA was inhibited by 5‐hydroxytryptamine (5‐HT) receptor antagonists (i.e., cyproheptadine and ketanserin) but not by the TAAR1 antagonist EPPTB. In gastric fundus strips that were previously contracted with 80 mmol/L KCl, the relaxant effect of β‐PEA intensified in the presence of 5‐HT receptor antagonists, which was inhibited by EPPTB and the adenylyl cyclase inhibitor MDL‐12,330A. The guanylyl cyclase inhibitor ODQ did not alter the relaxant effects of β‐PEA. In conclusion, β‐PEA exerted dual contractile and relaxant effects on rat gastric fundus. The contractile effect appeared to involve the recruitment of 5‐HT receptors, and the relaxant effect of β‐PEA on KCl‐elicited contractions likely involved TAAR1.

687 Topical Alginate Protection of Human Esophageal Epithelium for Gastro-Esophageal Reflux Disease. A Study Using Human Cell Culture and Biopsy Models

G A A b st ra ct s extra-hepatic malignancies in patients with IBD and co-existent PSC using the Explorys database. In total the Explorys database contains over 40 million unique patient records across the United States from over 400 hospitals. Methods: Explorys database from 19992014 was queried for adults with medical records of at least 4 years with a diagnosis of IBD (ICD-9: 556.xx, 555.xx). Patients were divided into 2 groups, those with ulcerative colitis (UC) and those with crohns disease (CD). Each group was further divided into patients that had PSC and those that did not. ICD-9 codes were used to identify extent and location of UC and CD, respectively. Medications were identified by generic and brand name. Analysis was completed using Chi-squared test and Odds ratio. A p-value < 0.05 was considered significant. Results: 2,170 of a total of 65,850 IBD patients had PSC. PSC was more common in UC than CD (p= 0.0001, Table 1). Caucasian males with UC were more likely to develop PSC (Table 1). While the majority of individuals with PSC were less than 65 years of age; interestingly, the data demonstrated that the incidence of PSC was highest in the age group 50-59 years (23.5%). In UC, the incidence of PSC increased with increased colonic involvement; however, disease distribution was not a factor in the CD. The current data also suggests that there is an increased risk of pancreatic cancer for both UC with PSC (p-value: 0.0001; OR: 6.53 95% (3.99-10.70)) and CD with PSC (p-value: 0.0001; OR 8.42 95% (5.14-13.80)). Conclusion: This study is the largest to date to assess the relationship of PSC and IBD. Confirming prior studies, the risk of PSC in greatest amongst Caucasian males with UC and its incidence increases with the degree of colonic involvement. The pooled data suggest a shift in the paradigm of PSC to an older patient population than previously thought, which may be reflective of the advent of potent anti-inflammatory medications limiting the degree of chronic inflammation. The relationship between CRC and PSC is well established; however a previously unknown phenomena, the increased risk of pancreatic cancer requires further exploration.