Facilitation of serotonin-induced contraction of rat mesenteric artery by ketamine

Ketamine is an anesthetic with hypertensive effects, which make it useful for patients at risk of shock. However, previous ex vivo studies reported vasodilatory actions of ketamine in isolated arteries. In this study, we reexamined the effects of ketamine on arterial tones in the presence and absence of physiological concentrations of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) by measuring the isometric tension of endothelium-denuded rat mesenteric arterial rings. Ketamine little affected the resting tone of control mesenteric arterial rings, but, in the presence of 5-HT (100~200 nM), ketamine (10~100 µM) markedly contracted the arterial rings. Ketamine did not contract arterial rings in the presence of NE (10 nM), indicating that the vasoconstrictive action of ketamine is 5-HT-dependent. The concentration-response curves (CRCs) of 5-HT were clearly shifted to the left in the presence of ketamine (30 µM), whereas the CRCs of NE were little affected by ketamine. The left shift of the 5-HT CRCs caused by ketamine was reversed with ketanserin, a competitive 5-HT(2A) receptor inhibitor, indicating that ketamine facilitated the activation of 5-HT(2A) receptors. Anpirtoline and BW723C86, selective agonists of 5-HT(1B) and 5-HT(2B) receptors, respectively, did not contract arterial rings in the absence or presence of ketamine. These results indicate that ketamine specifically enhances 5-HT(2A) receptor-mediated vasoconstriction and that it is vasoconstrictive in a clinical setting. The facilitative action of ketamine on 5-HT(2A) receptors should be considered in ketamine-induced hypertension as well as in the pathogenesis of diseases such as schizophrenia, wherein experimental animal models are frequently generated using ketamine.

Serotonin contracts the rat mesenteric artery by inhibiting 4-aminopyridine-sensitive Kv channels via the 5-HT2A receptor and Src tyrosine kinase

Serotonin (5-hydroxytryptamine (5-HT)) is a neurotransmitter that regulates a variety of functions in the nervous, gastrointestinal and cardiovascular systems. Despite such importance, 5-HT signaling pathways are not entirely clear. We demonstrated previously that 4-aminopyridine (4-AP)-sensitive voltage-gated K+ (Kv) channels determine the resting membrane potential of arterial smooth muscle cells and that the Kv channels are inhibited by 5-HT, which depolarizes the membranes. Therefore, we hypothesized that 5-HT contracts arteries by inhibiting Kv channels. Here we studied 5-HT signaling and the detailed role of Kv currents in rat mesenteric arteries using patch-clamp and isometric tension measurements. Our data showed that inhibiting 4-AP-sensitive Kv channels contracted arterial rings, whereas inhibiting Ca2+-activated K+, inward rectifier K+ and ATP-sensitive K+ channels had little effect on arterial contraction, indicating a central role of Kv channels in the regulation of resting arterial tone. 5-HT-induced arterial contraction decreased significantly in the presence of high KCl or the voltage-gated Ca2+ channel (VGCC) inhibitor nifedipine, indicating that membrane depolarization and the consequent activation of VGCCs mediate the 5-HT-induced vasoconstriction. The effects of 5-HT on Kv currents and arterial contraction were markedly prevented by the 5-HT2A receptor antagonists ketanserin and spiperone. Consistently, alpha-methyl 5-HT, a 5-HT2 receptor agonist, mimicked the 5-HT action on Kv channels. Pretreatment with a Src tyrosine kinase inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine, prevented both the 5-HT-mediated vasoconstriction and Kv current inhibition. Our data suggest that 4-AP-sensitive Kv channels are the primary regulator of the resting tone in rat mesenteric arteries. 5-HT constricts the arteries by inhibiting Kv channels via the 5-HT2A receptor and Src tyrosine kinase pathway.

Lumbar Sympathetic Ganglion Block with Alcohol for Plantar Hyperhidrosis / 대한통증학회지

BACKGROUND: Chemical lumbar sympathetic ganglion block could potentially be used to treat plantar hyperhidrosis; therefore, we analyzed the outcome of lumbar sympathetic ganglion block using alcohol for the treatment of plantar hyperhidrosis. METHODS: Between March 1992 and June 2003, 356 patients with plantar hyperhidrosis underwent lumbar sympathetic ganglion block using alcohol. All 356 patients were followed up for 2 years and the results evaluated. There were 185 and 171 male and female patients, respectively, with a mean age of 25.1 years, ranging from 15.3 to 56.5 years old. Lumbar sympathetic ganglion block using alcohol was performed with fluoroscopic guidance under local anesthesia. RESULTS: The recurrence rate after 2 years was 34%. Compensatory hyperhidrosis, ejaculation failure, lower back pain and genitofemoral neuritis developed as complications in 132, 4, 12 and 2 patients, respectively. Of the 356 patients, 65% were satisfied. CONCLUSIONS: Lumbar sympathetic ganglion block using alcohol is an effective and safe method for the treatment of plantar hyperhidrosis, but more information about the complications and relatively high recurrence rates should be provided to the patient.

A case of hyponatremia as the intial manifestation of Sheehan's syndrome / 대한산부인과학회잡지

No abstract available.

A Case of Pelvic and Abdominal Actonomycosis Associated with an Intrauterine Contraceptive / 대한산부인과학회잡지

Actinomycosis is a rare entity which presents some difficulties in establishing a correct preoperative diagnosis. Many actinomycotic pelvic infections in women are related to IUD use and the colonization rate appears to increase in accordance with the duration of IUD use. So, all women in IUD use are recommended to make cervicovaginal smear and pelvic infection associated with IUD use should be suspected to have actinomycoses. We report a case which presented painful mass on right upper and lower quadrant of abdomen of a 40-year-old women. We identified sulfur granules by histopathologic exam of surgically resected specimen. Eventually it proved to be pelvic and abdominal actinomycosis associated with the use of an intrauterine device. Because variable clinical pictures and infrequency of the disease make the diagnosis more difficult, increased alertness of clinicians and microbiologists to the presence of anaerobic organism as the cause of infection are needed to make an earlier and more correct diagnosis of actinomycoses and to further avoid any inappropriate treatment.

A Comparison of Intravaginal Misoprostol with Oral Dinoprostone for Labor induction at Term / 대한산부인과학회잡지

OBJECTIVE: To compare the safety and efficacy of intravaginal misoprostol versus oral dinoprostone for labor induction at term. METHODS: One hundred of patients at term were randomized to receive either 50microgram of misoprostol vaginally every 4 hours or dinoprostone 0.5mg orally every 1 hour for the maximum of six doses. Intravenous infusion of oxytocin was administered under such circumferences as the patient did not go into active labor after maximum dose, SROM was developed without an adequate contraction pattern, or the patient had arrest of dilatation(no change in cervical dilatation for 2 hours). We compared the frequency of oxytocin augmentation, administration to delivery interval, vaginal delivery rate within 12 hours and 24 hours, intrapartum complications, induction failure, mode of delivery, neonatal outcomes, and maternal complications between two groups. RESULTS: The average interval from administration to delivery was shorter in the misoprostol group(739.4+/-372.4min vs 1087.7+/-765.1min, p<0.05), but the interval from administration to vaginal delivery of each group was similar(724.3+/-375.4min vs 800.3+/-697.0min). Regarding the frequency of vaginal delivery within 24 hours, however, misoprostol group was higher than dinoprostone group(88% vs 56%, p<0.001). And oxytocin augmentation of labor occurred less commonly in misoprostol group than in dinoprostone group(20% vs 76%, p<0.05). Any statistically significant difference in intrapartum complications, mode of delivery, and neonatal or maternal adverse outcome was not appeared between these two group. CONCLUSION: Vaginal misoprostol is as effective and safe as oral dinoprostone for cervical ripening and induction of labor at term. In addition, vaginal misoprostol contributes the curtailment of labor induction expenditure due to its moderate price; misoprostol costs 100 won per 50microgram.