In vitro effects of intravenous anesthetics on the sphincter of Oddi strips of sheep

Sphincter of Oddi dysfunction: an evidence-based review

Sphincter of Oddi dysfunction is a painful syndrome that presents as recurrent episodes of right upper quadrant biliary pain, or recurrent idiopathic pancreatitis. It is a disease process that has been a subject of controversy, in part because its natural history, disease course and treatment outcomes have not been clearly defined in large controlled studies with long-term follow-up. This review is aimed at clarifying the state-of-the-art with an evidence-based summary of the current diagnostic and therapeutic approaches and modalities for sphincter of Oddi dysfunction.

Commonly used intravenous anesthetics decrease bladder contractility: An in vitro study of the effects of propofol, ketamine, and midazolam on the rat bladder

Aim:

This study was designed to test the hypothesis that propofol, ketamine, and midazolam could alter the contractile activity of detrusor smooth muscle.

Materials and Methods:

Four detrusor muscle strips isolated from each rat bladder (n = 12) were placed in 4 tissue baths containing Krebs-Henseleit solution. The carbachol (10 ⁻⁸to 10⁻⁴mol/L)-induced contractile responses as well as 5, 10, 20, 30, 40, 50 Hz electrical field stimulation (EFS)-evoked contractile responses of the detrusor muscles were recorded using isometric contraction measurements. After obtaining basal responses, the in vitro effects of propofol, ketamine, midazolam (10⁻⁵ to 10⁻³ mol/L), and saline on the contractile responses of the detrusor muscle strips were recorded and evaluated.

Results:

All the 3 drugs reduced the carbachol-induced and/or EFS-evoked contractile responses of rat detrusor smooth muscles in different degrees. Midazolam (10⁻⁴ to 10⁻³ mol/L) caused a significant decrease in the contractile responses elicited by either EFS or carbachol (P=0.000−0.013). Propofol (10⁻³mol/L) caused a decrease only in EFS-evoked contractile responses (P=0.001−0.004) and ketamine (10⁻³mol/L) caused a decrease only in carbachol-induced contractile responses (P=0.001−0.034).

Conclusion:

We evaluated the effects of the 3 different intravenous anesthetics on detrusor contractile responses in vitro and found that there are possible interactions between anesthetic agents and detrusor contractile activity. The depressant effects of midazolam on the contractile activity were found to be more significant than ketamine and propofol. Despite the necessity of further studies, it could be a piece of wise advice to clinicians to keep the probable alterations due to intravenous anesthetics in mind, while evaluating the results of urodynamic studies in children under sedation.

Effect of four medications associated with gastrointestinal motility on Oddi sphincter in the rabbit

AIM

Modulatory drugs of gastrointestinal (GI) motility are a possibility for use to relieve the main clinical presentation of sphincter of Oddi (SO) dysfunctions which are not easily distinguished from those occurring in high prevalence functional GI disorders. The aim of this study was to investigate the effects of GI motility modulators including pinaverium, domperidone, trimebutine, and tegaserod on the contractile activity of SO stimulated by carbachol in the rabbit.

METHODS

The contraction responses precontracted by carbachol (0.1 microM) of in vitro rabbit SO rings were evaluated before and after the addition of a series concentration (10(-13) to 10(-3)M) of pinaverium, domperidone, trimebutine, and tegaserod.

RESULTS

Pinaverium induced a concentration-dependent relaxation of isolated SO rings (10(-13) vs. 10(-7) vs. 10(-3)M = 16.6 +/- 4.8 vs. 47.1 +/- 5.5 vs. 81.2 +/- 6.2%, p < 0.001 by ANOVA) precontracted with carbachol (0.1 microM). Tegaserod did not significantly effect (10(-13) vs. 10(-7) vs. 10(-3)M = 2.3 +/- 2.2 vs. 6.7+/- 2.1 vs. 10.1 +/- 2.3%, p > 0.05 by ANOVA) SO motility, but domperidone seemed to stimulate SO contractions (10(-12) vs. 10(-7) vs. 10(-3)M = -2.2 +/- 1.5 vs. -13.9 +/- 2.0 vs. -21.0 +/- 2.7%, p < 0.05 by ANOVA). At low doses (10(-13) to 10(-7)M), trimebutine stimulated SO contraction (-8.7 +/- 1.4 vs. -9.3 +/- 2.0%); however, high doses (10(-6) to 10(-3)M) of trimebutine inhibited SO motility (-5.9 +/- 1.7 vs. 14.5 +/- 2.0%, p < 0.05 by ANOVA).

CONCLUSION

Pinaverium totally inhibits contractions induced by carbachol and tegaserod has no effect on carbachol-induced contractions. Domperidone stimulates contractions induced by carbachol. Trimebutine could either stimulate or inhibit SO contractions depending on its dosage.

Investigation of relaxant effects of propofol on sheep sphincter of Oddi

BACKGROUND/AIMS

Intravenous anesthetics are often used for conscious sedation in endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincter of Oddi (SO) manometry. This study was designed to investigate the effects of propofol on sheep SO.

METHODS

SO rings were mounted in a tissue bath and tested for changes in isometric tension in response to propofol (10(-8)-10(-4)M) in the presence or absence of L-NAME (3 x 10(-5)M), a non-specific inhibitor of nitric oxide (NO) synthase; indomethacin (10(-5)M), an inhibitor of cyclooxygenase; glibenclamide (10(-5)M), an inhibitor of ATP-sensitive potassium channels; tetraethylammonium (3 x 10(-4)M), inhibitors of calcium-activated potassium channels; 4-aminopyridine (10(-3)M), a voltage-dependent potassium channel blocker. Furthermore, we investigated the Ca(2+) antagonist feature of propofol in precontracted SO rings by CaCl(2).

RESULTS

Carbachol (10(-9)-10(-5)M) induced concentration-dependent contraction responses in the SO rings. Propofol (10(-8)-10(-4)M) produced concentration-dependent relaxation on isolated SO rings precontracted by carbachol (10(-6)M). Preincubation of SO rings by L-NAME (3 x 10(-5)M), indomethacin (10(-5)M), glibenclamide (10(-5)M), and 4-aminopyridine (10(-3)M) did not produce a significant alteration on propofol-induced relaxation responses (p > 0.05), while preincubation by tetraethylammonium (3 x 10(-4)M) significantly decreased the propofol-induced relaxation responses (p < 0.05). Propofol (10(-8)-10(-4)M) induced concentration-dependently relaxations in precontracted isolated SO rings by CaCl(2).

CONCLUSION

The results suggest that propofol induced concentration-dependent relaxations in precontracted isolated SO rings. These relaxations are independent from NO, cyclooxygenase metabolites, and opened ATP-sensitive and voltage-dependent potassium channels. Opened Ca(2+)-sensitive K(+) channels and inhibited L-type Ca(2+) channels existing in smooth muscle by propofol can contribute to these relaxations. Propofol can be beneficial as alternative drugs for obtaining selective relaxation during SO manometry after controlled clinical studies.

Neurohormonal regulation of the sphincter of Oddi

The control of sphincter of Oddi (SO) motor activity is complex and involves interactions between the SO smooth muscle with nerves, bioactive agents, and presumably interstitial cells of Cajal. Disturbances in SO motility are known to be related to painful clinical conditions, such as SO dysfunction and acute pancreatitis. Understanding normal SO motility and comparing this to disturbed SO motility patterns may identify mechanisms that could be targeted for future pharmacologic intervention. The effect on SO motility of recently identified neurotransmitters/neuropeptides, such as purines and orexins, is currently being determined. Furthermore, because the control of SO motility is complex, investigations with known bioactive agents, such as cholecystokinin and nitric oxide, are continuing. This review summarizes research investigating SO motility and function performed in 2005 and 2006.