tetrodotoxin and Cholelithiasis

We studied the influence of the inflammatory state of the gallbladder with gallstones on its response to cholecystokinin (CCK). Responses to CCK were evaluated in isolated human gallbladder strips incubated with pharmacological antagonists. Gallbladders from patients with gallstones were classified as having mild and severe chronic cholecystitis. Healthy gallbladders were collected from liver donors. In donor gallbladders, the CCK contraction was abolished with the CCK-A receptor antagonist, L-364718, and significantly reduced by indomethacin. In gallbladders with gallstones, only mild cholecystitis showed a decreased contraction to CCK. In gallbladders with gallstones, no involvement of prostaglandins in the CCK response was observed. In severe cholecystitis, CCK contractile effect was reduced by the serotonin receptor antagonist methysergide. In healthy gallbladder, the contraction provoked by CCK is mediated by CCK-A receptors and modulated by prostaglandins. The presence of gallstones in the gallbladder is correlated with a loss of prostaglandins-modulated CCK contraction. However, the excessive release of serotonin in advanced cholecystitis normalizes the contraction to CCK, suggesting that the state of cholecystitis affects the pool of inflammatory mediators responsible for gallbladder CCK-altered motility.

Topics: Acetylcholine; Adult; Atropine; Cholecystectomy; Cholecystitis; Cholecystokinin; Cholelithiasis; Drug Interactions; Female; Gallbladder Emptying; Histamine; Humans; Indomethacin; Male; Middle Aged; Muscle Contraction; Organ Culture Techniques; Probability; Propranolol; Sensitivity and Specificity; Serotonin; Severity of Illness Index; Tetrodotoxin

The aim of this study was to determine the role of nitric oxide (NO), as the primary neurotransmitter of non-adrenergic, non-cholinergic (NANC) innervation, in stone-diseased and stone-free human gallbladders.. Human gallbladder muscle strips were mounted in modified Krebs-Henseleit solution with atropine (1 mM), guanethidine sulfate (5 mM) and aerated with Carbogen. Electric field stimulation (EFS) (70 V, 0.5 ms, 100 pulses) was used to activate NANC nerves. N-omega-nitro-L-arginine (L-NNA, 100 mM) and L-arginine (L-Arg, 120 mM) were used to manipulate the NO-synthase. Gallbladder slices were stained by using the alkaline phosphatase, anti-alkaline phosphatase (APAAP) method for histological examination.. In the control group (basal tone, 8.94 +/- 1.17 mN) caused a frequency-dependent reduction of basal tone (1 Hz = 5.73 +/- 0.81 mN; 3 Hz = 5.18 +/- 0.65 mN; 10 Hz = 4.63 +/- 0.49 mN), inhibition of NO-synthesis with L-NNA increased the tone (7.63 +/- 0.76 mN). Stone-diseased groups were divided into two groups (contractor and subcontractor), according to their ability to contract by CCK. Under the influence of EFS the contractor group (basal tone = 7.79 +/- 0.93 mN) reacted like the control group, but was frequency-independent and, additionally, showed spontaneous phasic contractions. In the sub-contractor group (basal tone 4.13 +/- 0.65 mN) EFS only decreased the frequency of spontaneous phasic contractions. L-NNA caused an increase in tone (5.97 +/- 0.84 mN) and frequency. L-arginine, the substrate for NO-synthase, significantly reversed this effect, indicating the dependence on NO. Histologically, the contractor group showed a wrinkled mucosal membrane and low-grade inflammation. Shallow mucosa, necrosis and high-grade inflammation were found in the sub-contractor group.. In vitro, NANC relaxation of human gallbladder is NO dependent. The motility of stone-diseased gallbladders is modulated by NO and seems to depend on the degree of scarification.

Topics: Adult; Aged; Cholelithiasis; Electric Stimulation; Enzyme Inhibitors; Female; Gallbladder; Gastrointestinal Agents; Humans; In Vitro Techniques; Male; Middle Aged; Muscle Contraction; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; Sincalide; Tetrodotoxin

Calcitonin gene-related peptide (CGRP) is a neurotransmitter present in the peripheral ends of sensory neurons of the gut and may modulate reflexes of the enteric nervous system. We studied the release of CGRP in normal human gallbladders and in those containing gallstones to test the hypothesis that abnormalities of regulation of CGRP release participate in gallstone formation. Human gallbladder strips were obtained from histologically normal organs removed during liver surgery (n = 8) or from patients operated upon for symptomatic cholelithiasis (n = 14). After removal of the mucosa, muscle strips were superfused with oxygenated Kreb's buffer in an organ bath at 37 degrees C. Pharmacologic agents were added to the superfusate and samples were collected at 2-min intervals for analysis. CGRP release was measured by a sensitive and specific radioimmunoassay and adjusted for tissue weight. In normal gallbladders, CGRP release was stimulated sixfold over basal by capsaicin (10(-5) M) to 363 +/- 75 pg per gram of muscle per 2 min. This release was abolished by addition of somatostatin (SS) or the neural blocker tetrodotoxin (TTX). Lesser degrees of CGRP release were observed after nonspecific stimulation with K+ or phosphodiesterase inhibition with caffeine. In gallbladders with gallstones, capsaicin-induced CGRP release was 74 +/- 16 pg per gram of muscle per 2 min (20% of normal, P < 0.001). Release induced by caffeine and K+ was also inhibited compared to normal gallbladder strips. Release of CGRP from diseased strips was abolished by TTX and inhibited by SS to degrees similar to normal tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Calcitonin Gene-Related Peptide; Cholecystitis; Cholelithiasis; Gallbladder; Humans; Somatostatin; Tetrodotoxin