Labor induction using modified metreurynters plus oxytocin at an institution in Japan: a retrospective study

OBJECTIVE

The authors evaluated the effectiveness and safety of "neo-metoro" or 'mini-metoro" metreurynters plus oxytocin for labor induction and assessed differences in parturition outcomes, according to the metreurynter used at induction initiation.

MATERIALS AND METHODS

The authors retrospectively reviewed 146 consecutive women with live singleton pregnancies, and who underwent induction. Parturition outcomes were vaginal delivery achieved within the planned schedule (VDPS), vaginal delivery finally achieved (VDF), and induction-to-delivery interval (IDI). Women were divided into neo-metoro, mini-metoro, and without metreurynter groups based on metreurynter use at induction initiation. The authors examined the relationships of metreurynter groups with factors, parturition outcomes, and adverse events. In 113 women who underwent two-day induction, the authors calculated IDI and adjusted odds ratio (AOR) for achieving delivery per unit time.

RESULTS

VDPS rates were 65% in nulliparous and 81% in multiparous women. VDF rates were 78% in nulliparous and 96% in multiparous women. AORs for VDPS were 0.30 in nulliparous women and 0.18 in Bishop score (BS) 1-3 class. AORs for VDF were 0.04 in BS1-3 class and 0.14 in BS4-5 class. In 113 women undergoing two-day induction, AORs for achieving delivery per unit time were 0.45 in nulliparous women, 0.46 in obese women, and 0.48 in BS1-3 class. Neo-metoro use at induction initiation tended to reduce IDI.

CONCLUSIONS

Labor induction using these metreurynters plus oxytocin is safe and effective. The advantages of neo-metoro over mini-metoro use at induction initiation remain unclear; neo-metoro use at induction initiation may reduce IDI.

Clinical application of a new compact CT system to assess 3-D images for the preoperative treatment planning of implants in the posterior mandible A case report

When treatment planning before placing dental implants in the posterior region of the mandible, the locations of the inferior alveolar nerve and mental foramen need to be ascertained, as they determine the bone height available and the implant length selected. The purpose of this study was to introduce the clinical application of a newly developed compact computed tomography system (Ortho-CT) to assess three-dimensional (3-D) images for the preoperative treatment planning of implants in the posterior region of the mandible. To evaluate the 3-D images, we scanned using the Ortho-CT system the mandible with a radiopaque template placed in the posterior region. The Ortho-CT images provided excellent information for evaluating the morphology of the mandible, and for showing the location of the inferior alveolar nerve, mental foramen and the relationship of the template to the bone. We consider that Ortho-CT is a useful aid to preoperative treatment planning of implant therapy in the mandible.

Comparison of DNA sequence and transactivation activity of open reading frame 62 of Oka varicella vaccine and its parental viruses

When nucleotide sequences of Oka vaccine and its parental viruses of varicella-zoster virus (VZV) were compared in 5 open reading frames (ORFs) including glycoprotein C (gC) and 4 immediate-early genes, mutations were detected only in gene 62 which is one of the immediate-early genes. Compared with its parental virus, the vaccine virus contained 15 nucleotide substitutions. With the differentiation method using the simplified restriction-enzyme fragment length polymorphism analysis by Nae I and Bss HII, which was established based on the sequence analysis data in this study, the Oka vaccine virus could be distinguished from its parental virus. Studies of the regulatory activities of the ORF62 gene product (IE62) in a transient assay indicate the IE62 of the parental virus had a stronger transactivational activity than that of the vaccine virus against immediate-early, early and late gene promoters. These data suggest that gene 62 might have an important role for attenuation of VZV. This is the first report in which many substitutions of nucleotides in gene 62 of Oka vaccine virus was found, compared with that of Oka parental virus.

Aldosterone-producing adenoma with prolonged amelioration by dexamethasone

Secretion of aldosterone from aldosterone-producing adenoma (APA) is to some degree under the control of ACTH and the suppressible effect of glucocorticoid on plasma aldosterone concentration (PAC) and blood pressure has been reported to be transient. We report a rare case of aldosteronism due to APA in which PAC and blood pressure were well controlled with small dose dexamethasone for over one year. No chimeric gene of glucocorticoid-remediable aldosteronism (GRA) was found in DNA of APA and leukocytes from peripheral blood and 17alpha-hydroxylase deficiency (17-OH-D) was ruled out by endocrinological examinations, this case indicates the possibility of an unknown mechanism of ACTH-dependent APA.

Inhibitory effects of amlexanox on carbachol-induced contractions of rabbit ciliary muscle and guinea-pig taenia caecum

Instillation of amlexanox, an anti-allergic drug, over a long period improves myopia in some allergy patients and in monkeys. The relaxing effect of amlexanox on persistent contraction of ciliary muscle may be involved in the improvement of myopia. In this study, the mechanism of the noncompetitive inhibition of carbachol-induced contractions by amlexanox (1-100 microM) was investigated in isolated smooth muscle preparations of the rabbit ciliary body and guinea-pig taenia caecum. In ciliary muscles, amlexanox (100 microM) inhibited both the phasic and tonic components of carbachol-induced contractions even in the presence of cyclopiazonic acid (10 microM) where the function of the sarcoplasmic reticulum was impaired, while diltiazem (3.2, 32 microM) did not. In taenia caecum, diltiazem (3.2 microM) slightly inhibited the phasic component and abolished the tonic component of carbachol-induced contractions. Amlexanox also abolished the tonic component, but it did not decrease the 45Ca2+ uptake into taenia caecum smooth muscle cells induced by carbachol. Amlexanox did not increase the cyclic adenosine monophosphate (cyclicAMP) content of ciliary muscles in the presence of 3-isobutyl-1-methylxanthine (10 microM), while forskolin (1 microM) did. Gel-shift assay showed that the inhibition of carbachol-induced contractions by amlexanox was accompanied by a decrease in phosphorylation of the 20-kDa myosin light chain in taenia caecum tissue preparations. Amlexanox had no effect on calmodulin activity, whereas it inhibited phosphorylation of the myosin light chain by purified myosin light-chain kinase from chicken gizzard. These results suggested that amlexanox may not affect either Ca2+ mobilization or calmodulin activity, although it inhibits myosin light-chain kinase, which may inhibit carbachol-induced contraction.

Myosin light chain phosphorylation and Mn2+-dependent acetylcholine-induced contractions in guinea pig vas deferens

We have reported that noradrenaline but not K+ induced a sustained and dose-dependent contraction without extracellular Ca2+ and Mn2+ in Ca2+-depleted Mn2+loaded vas deferens from the guinea pig. The Mn2+dependent noradrenaline-induced contractions developed without an increase in phosphorylation of 20-kDa myosin light chain. To clarify whether such an unusual Mn2+dependent contraction was induced only by noradrenaline or not, we examined effects of acetylcholine on Ca2+-depleted Mn2+-loaded guinea pig vas deferens. Acetylcholine (1 microM(-1) mM) induced a sustained dose-dependent contraction without extracellular Ca2+ or Mn2+. W-7 (10 microM or 100 microM) and wortmannin (1 microM) both reduced the Mn2+dependent acetylcholine-induced contractions similarly to Ca2+-dependent acetylcholine-induced contractions in isolated vas deferens without either Ca2+ depletion or Mn2+ loading. However, the Mn2+-dependent acetylcholine-induced contractions developed without a significant increase in the phosphorylation of the myosin light chain determined by urea-glycerol polyacrylamide gel electrophoresis and immunoblotting. These results indicate that acetylcholine as well as noradrenaline induces Mn2+-dependent contraction and are consistent with our previous assumption that Mn2+ may preferentially support receptor-mediated contractions in the guinea pig isolated vas deferens. The results also suggest that the activation of myosin light chain kinase is essential for the development of Mn2+-dependent acetylcholine-induced contractions, and that Mn2+ may accelerate formation of non-phosphorylated attached cross-bridges during receptor activation.

Oka varicella vaccine is distinguishable from its parental virus in DNA sequence of open reading frame 62 and its transactivation activity

When the nucleotide sequences of the Oka vaccine and its parental varicella-zoster virus (VZV) were compared in 6 open reading frames (ORFs), glycoprotein C (gC) and 5 transactivator genes, mutations were detected only in the immediate-early gene 62. The vaccine virus contained a mixture of different sequences that had variations at 15 nucleotide positions, but only one sequence was found for the Oka parental virus gene 62. The Oka vaccine virus gene 62 could be distinguished from the parental virus gene using a simplified restriction-enzyme fragment length polymorphism analysis, using NaeI and BssHII. This analysis was based on the sequence data obtained in this study. Studies of the regulatory activities of the ORF62 gene product (IE62) in a transient transfection assay indicated that IE62 of the parental virus had a stronger transactivational activity than that of the vaccine virus in activating immediate-early, early, and late gene promoters. These data suggest that IE62 might play an important role in the attenuation of VZV.

Expression of human herpesvirus 6B rep within infected cells and binding of its gene product to the TATA-binding protein in vitro and in vivo

We have characterized the human herpesvirus 6B (HHV-6B) rep gene, which is a homologue of the adeno-associated virus type 2 rep and is unique in the herpesvirus family. Three transcripts, 9.0, 5.0, and 2. 7 kb (the major transcript), were detected by Northern blotting using an HHV-6B rep probe under late conditions. We investigated the expression kinetics of the rep gene using cycloheximide (CHX) and phosphonoformic acid (PFA), which are inhibitors of protein synthesis and viral DNA synthesis, respectively. The 5.2-kb transcript was mainly detected in the absence of protein biosynthesis upon infection, and none of the 9.0-, 5.0-, and 2.7-kb transcripts detected under the late conditions were detected in the presence of CHX and PFA. Sequences obtained from a cDNA library showed that the 5.0- and 2.7-kb transcripts were spliced from two and three exons, respectively, and the 2.7-kb transcript was more abundant. Immunohistochemistry using an antibody raised against the HHV-6 rep gene product (REP) revealed that REP was mainly present in the nucleus of MT-4 cells within 24 h after infection with HHV-6B. Using pull-down assays, coimmunoprecipitation, and a mammalian two hybrid system, we showed that HHV-6 REP binds to a transcription factor, human TATA-binding protein, through its N-terminal region.

[The outcome of treatment with adjusted dose of 131I to thyroid weight for Graves' disease by estimation of effective half life using a single radioiodine uptake measurement]

In the determination of therapeutic 131I doses, it takes several days to measure effective half life (EHL) of radioiodine in thyroid glands (Ordinary method). We suggested the new method to estimate EHL by a single radioiodine uptake measurement (INDEX method). We evaluated the outcome of 131I treatment with these two methods in outpatients with Graves' disease. Eighty outpatients were treated with INDEX method (Group I) and 108 outpatients with Ordinary method (Group O). At the 5-yr follow up, the incidence of hypothyroidism in Group I was 22.5%, subclinical hypothyroidism 8.8%, euthyroidism 30.0%, subclinical hyperthyroidism 13.7% and hyperthyroidism 25.0%. In Group O, 17.6% of the patients were hypothyroid, 16.7% subclinical hypothyroid, 30.5% euthyroid, 9.3% subclinical hyperthyroid and 25.9% hyperthyroid. There were no significant differences between these two methods. We conclude that INDEX method surpasses Ordinary method in timesaver and is equal in effectiveness.

Proton delivery in NO reduction by fungal nitric-oxide reductase. Cryogenic crystallography, spectroscopy, and kinetics of ferric-NO complexes of wild-type and mutant enzymes

Fungal nitric-oxide reductase (NOR) is a heme enzyme that catalyzes the reduction of NO to N(2)O through its ferric-NO complex, the first intermediate of the catalysis. Crystal structures of the ferric-NO forms of wild type (WT) fungal NOR, and of the Ser(286) --> Val and Ser(286) --> Thr mutant enzymes were determined to 1.7-A resolution at cryogenic temperature (100 K). This shows a slightly tilted and bent NO binding to the heme iron, in sharp contrast to the highly bent NO coordination found in ferrous hemoproteins. In the WT structure, a specific hydrogen-bonding network that connects the active site to the solvent was identified, H(2)O(Wat(74))-Ser(286)-H(2)O(Wat(33))-Asp(393)-solvent. Wat(74) is located 3.10 A from the iron-bound NO. Replacement of Ser(286) with Val or Thr scarcely alters the NO coordination structure but expels the water molecules, Wat(74) from the active site. The Asp(393) mutation does not influence the position of Wat(74), but disrupts the hydrogen-bonding network at Wat(33), as evidenced by enzymatic, kinetic, and spectroscopic (resonance Raman and IR) results. The structural changes observed upon the Ser(286) or the Asp(393) mutation are consistent with the dramatic loss of the enzymatic activity for the NO reduction of fungal NOR. We have conclusively identified the water molecule, Wat(74), adjacent to the iron-bound NO as a proton donor to the Fe-NO moiety. In addition, we find the hydrogen-bonding network, H(2)O(Wat(74))-Ser(286)-H(2)O(Wat(33))-Asp(393), as a proton delivery pathway in the NO reduction reaction by fungal NOR.

[Changes in isolated ciliary muscle caused by repeated instillation of carbachol ointment in rabbits and effect of topically applied amlexanox]

PURPOSE

We investigated changes in ciliary muscle caused by continual contraction in rabbits and evaluated the efficacy of topically applied amlexanox, which relaxes the ciliary muscle, on such changes.

SUBJECTS AND METHODS

After topical application of carbachol ointment 5 times daily for 2 weeks, the contractile responses of isolated ciliary muscles to carbachol were measured isometrically, and the ciliary smooth muscle fibers were stained with phosphotungstic acid and hematoxylin and observed histologically. 1% amlexanox solution was instilled 5 minutes before every instillation of carbachol ointment.

RESULTS

Repeated topical carbachol ointment caused decreases in both contractile responses of isolated ciliary muscles to carbachol and number of ciliary smooth muscle fibers stained by phosphotungstic acid and hematoxylin. Amlexanox inhibited these changes.

CONCLUSION

We found that continual contraction of the ciliary muscle caused functional and histological changes in it. These changes are thought to occur in some diseases which cause excessive contraction of the ciliary muscle. Topical amlexanox might be useful for these diseases.

Norepinephrine- and K+-induced Mn2+-dependent contractions and the dynamics of intracellular Mn2+ changes in dispersed smooth muscle cells from Ca2+-depleted Mn2+-loaded vas deferens of the guinea pig

The cellular mechanisms of norepinephrine (NE)-induced Mn2+-dependent contractions were investigated in dispersed smooth muscle cells from guinea pig vas deferens by characterizing the effects of NE and K+ on cell length observed by videotape microscopy and on intracellular Mn2+ and Ca2+ concentration ([Mn2+]i and [Ca2+]i) observed by confocal microscopy. Both stimulants induced slow sustained contraction in Ca2+-depleted, Mn2+-accumulated cells (Mn2+-loaded cells), whereas they induced biphasic contractions in normal cells that were neither Ca2+-depleted nor Mn2+-loaded. In both conditions, the number of cells responding to NE as well as the magnitude of NE-induced contractions increased in a dose-dependent manner. Contractions induced by K+ in Mn2+-loaded strip preparations were markedly smaller than those induced by NE. Although individual K+-induced contractions in responsive Mn2+-loaded cells were as large as those induced by NE, a much smaller percentage of Mn2+-loaded cells was responsive to K+ than to NE. These results are consistent with the idea that the contractions of strip preparations may reflect the magnitude of the contractions of individual cells as well as the percentage of responsive cells in the preparations. Inconsistent with the contractions, the [Mn2+]i rise induced by K+ was larger than that induced by NE, and the percentage of cells responsive to K+ was larger than that responsive to NE. These results suggest that NE may increase the Mn2+ sensitivity of contractile elements.

Myosin light chain phosphorylation and Mn2+ -dependent norepinephrine-induced contractions in guinea-pig vas deferens

We have reported that norepinephrine but not K+ induced a sustained and dose-dependent contraction without extracellular Ca2+ and Mn2+ in Ca2+-depleted Mn2+-loaded vas deferens from the guinea-pig. In the present study, we determined the phosphorylation of the 20-kDa myosin light chain and examined the effects of inhibitors of calmodulin and myosin light chain kinase on the Mn2+-dependent norepinephrine-induced contraction in order to evaluate the contribution of phosphorylation to this contraction. W-7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], ML-9 [1-(5-chloronaphthalene-1-sulfonyl)-homopiperazine] and wortmannin inhibited this contraction. However, the Mn2+-dependent norepinephrine-induced contraction developed without a significant increase in the phosphorylation of the 20-kDa myosin light chain. In beta-escin-permeabilized preparations, Mn2+ induced contractions that were inhibited by ML-9. These results suggest that the activation of myosin light chain kinase is essential for the development of Mn2+-dependent norepinephrine-induced contractions and that the phosphorylation of myosin light chain may act as a trigger for these contractions.

[The outcome of adjusted accumulation dose of treatment of Graves' disease]

We evaluated the outcome of 131I treatment of Graves' disease in two different protocols (old and new protocol) of adjusted accumulation dose from 1988 to 1995. Adjusted accumulation doses of patients with above 50 g thyroid weights were increased by 5-20 Gy/g tissue in new protocol compared to those in old one. In 166 patients treated with single and plural doses of 131I treatment in 1990 (Group In), the therapeutic doses were calculated according to new protocol and in 130 patients in 1988 (Group Io), according to old one, modification of Quimby's formula. The patients treated with plural doses were classified as hyperthyroidism because the efficacies of the first treatments with 131I were insufficient. At the 5-yr follow up, the incidence of hypothyroid in Group In was 9%, subclinical hypothyroid 17%, euthyroid 30%, subclinical hyperthyroid 7%, hyperthyroid 37%. In Group Io, 11% of the patients were hypothyroid, 6% subclinical hypothyroid, 29% euthyroid, 3% subclinical hyperthyroid, 51% hyperthyroid. The incidence of hyperthyroid in Group In was lower than that in Group Io (p < 0.05). There were no significant differences in hypothyroid and euthyroid. In conclusion, we suggest that an adjusted dose of 131I in relation to the patients' thyroid weight shows some room for improvement.

Cushing's syndrome due to bilateral adrenocortical adenomas with different pathological features

A 48-year-old woman with Cushing's syndrome due to bilateral adrenocortical adenomas is reported. The patient presented with a typical Cushingoid appearance. The serum cortisol level was elevated with loss of the diurnal rhythm and the plasma adrenocorticotropic hormone (ACTH) level was undetectable. Dynamic testing showed no suppression of urinary 17-OHCS by high-dose dexamethasone and no stimulation by metyrapone. An abdominal computed tomography (CT) scan showed bilateral adrenal tumors. Bilateral adrenalectomy was performed. The right adrenal gland contained a tumor that was encapsulated and consisted mainly of compact cells. The surrounding cortex was atrophic. The left adrenal gland contained an encapsulated tumor composed predominantly of clear cells. There were numerous small adrenocortical nodules in the surrounding cortex. Immunohistochemical analysis of steroidogenic enzymes (P450scc, 3beta-HSD, P450c21, P450c17 and P450c11) was performed. Immunoreactivity of all the enzymes was intense in the compact cells of the right adrenocortical adenoma, while the adjacent non-neoplastic cortex was negative for the enzymes. In the left adrenal tumor, the immunoreactivity of 3beta-HSD was intense, while that of P450c17 was weak. In the adrenocortical nodules, 3beta-HSD activity was sporadically observed. G protein genes encoding Gs alpha and Gi2 were examined for activating mutations at codons 201 and 227 (Gs alpha) and codons 179 and 205 (Gi2 alpha) in the bilateral adrenal tumors, but no mutations were found. The bilateral adenomas of this patient showed marked differences in microscopic and immunohistochemical studies, suggesting that the capacity of steroidogenesis differs between the right and left tumors.

Effects of phorbol-12,13-dibutyrate and protein kinase C inhibitors on Mn(2+)-dependent norepinephrine-induced contractions involving increase in Mn2+ sensitivity in Ca(2+)-depleted vas deferens of the guinea pig

1. In Ca(2+)-depleted Mn(2+)-loaded vas deferens from the guinea pig (Mn-loaded preparations), norepinephrine (NE) induced a tonic contraction dose dependently without extracellular Ca2+ and Mn2+. 2. In the beta-escin skinned vas deferens, Mn2+ as well as Ca2+ induced contractions. Guanosine triphosphate and NE increased the sensitivity of contractile mechanisms to these divalent cations. 3. Phorbol-12,13-dibutyrate (PDBu) did not induce contractions in normal (Mn(2+)-unloaded Ca(2+)-contained) preparations, whereas it induced slow sustained contractions dose dependently in Mn-loaded preparations. Although cumulative applications of PDBu desensitized the preparations to this phorbol ester, the desensitization did not affect Mn(2+)-dependent NE-induced contractions. PDBu did not affect the dose-response relation of NE in Mn-loaded preparations. 4. Staurosporine (10-100 nM) preferentially inhibited NE-induced contractions in normal and in Mn-loaded preparations to that induced by K+ in normal preparations. However, bisindolylmaleimide I (1 microM) did not inhibit NE-induced contractions in normal and Mn-loaded preparations but abolished PDBu-induced contractions. 5. These results suggest that the NE-induced increase in the Mn2+ sensitivity of contractile mechanisms contributes to Mn(2+)-dependent NE-induced contractions, which may not involve the activation of protein kinase C.

Effects of the functional elimination of sarcoplasmic reticulum on the manganese-dependent norepinephrine-induced contractions of the guinea pig vas deferens

We investigated the effects of inhibitors of the sarcoplasmic reticulum (SR) functions on the tonic contractions induced by norepinephrine (NE) in the Ca(2+)-depleted Mn(2+)-loaded vas deferens of the guinea pig in the absence of both Ca2+ and Mn2+ (Mn(2+)-dependent NE-contraction). In control preparations without Ca(2+)-depletion and Mn(2+)-loading, either cyclopiazonic acid (CPA, 10 microM) or ryanodine (RYA, 3 microM) inhibited the initial phasic and tonic components but not the large phasic component of NE-induced contraction in normal medium containing 2.2 mM Ca2+. In contrast, CPA did not affect the Mn(2+)-dependent NE-contractions. The inhibitory effect of RYA slowly developed with each repetition of the Mn(2+)-dependent NE-contraction and the magnitude of the inhibition was slight. A23187 (10 microM) inhibited the NE-induced contractions of the control preparations in the same manner as CPA and RYA. Although A23187 did not induce contractions in the Mn(2+)-loaded preparations, A23187 augmented the Mn(2+)-dependent NE-contractions. The augmented tonic contractions returned to the resting level by washing NE and A23187. The augmentation remained for 3 successive contractions in the absence of A23187. However, the 2nd application of A23187 did not augment the contraction. These results suggest that neither Mn(2+)-release from SR nor Mn(2+)-influx from the extracellular space contributes to the Mn(2+)-dependent NE-contractions. We concluded that NE induces Mn(2+)-dependent contractions by increasing Mn2+ sensitivity of contractile processes but not by increasing intracellular Mn2+ concentration.

The specific effect of Mn2+ on the tonic components of receptor-mediated contractions in isolated vas deferens of the guinea pig

Intracellular accumulation of Mn2+ augmented the contractions induced by norepinephrine and acetylcholine in the guinea pig isolated vas deferens. Contractions repeatedly induced by norepinephrine, acetylcholine, or a high concentration of K+ decreased depending on the incubation time in Ca(2+)-free medium. The rate of decrease of all contractions was delayed by intracellularly accumulated manganese. In the Mn(2+)-loaded preparations, the tonic components of the contractions induced by norepinephrine and acetylcholine, but not K+, were highly resistant to extracellular Ca2+ elimination. Ryanodine abolished the initial phasic component but did not affect the tonic component of norepinephrine- and acetylcholine-contractions in Mn(2+)-loaded preparations in Ca(2+)-free medium. In Ca(2+)-depleted preparations, the tonic contraction induced by norepinephrine was restored after the Mn(2+)-loading procedure, and the magnitude of this tonic contraction was comparable to the tonic component of the norepinephrine contraction in the normal medium before Mn2+ loading. The tonic contraction was reproducible in medium without either Mn2+ or Ca2+. These results suggested that intracellular Mn2+ can support norepinephrine-induced tonic contractions. In the Ca(2+)-depleted Mn(2+)-loaded preparations, K+ also induced a tonic contraction in the presence of extracellular Mn2+. However, this contraction was much smaller than that induced by norepinephrine. These results suggested that intracellular Mn2+ augmented contractions not only via an increase in intracellular Ca2+ availability but also via the direct action of Mn2+ on contractile mechanisms, and that this action is highly specific for developing and/or maintaining tonic contractions mediated by receptor activation in the guinea pig isolated vas deferens.

Spontaneous tone in different types of longitudinal muscle preparations of guinea pig ileum

Spontaneous tone of longitudinal muscle in guinea pig ileum was investigated in three types of preparations, intact segment preparation, segment preparation deprived of the mucosal layer and longitudinal strip preparation. Tone was defined as the sustained contraction that was lost by 10(-7) M atropine in the isotonically recorded manner. The magnitudes of tone were constant for at least 3 hr in the two types of segment preparations. Contractions in response to 10(-6) M acetylcholine, which were induced 9 times with an interval of 20 min between each induction, were almost identical throughout the period. In the longitudinal strip preparation, on the other hand, the tone gradually decayed and was eventually lost, while the amplitudes of acetylcholine-induced contractions were reciprocally increased. The tone in the intact segment preparation was reduced to 19% of the control by tetrodotoxin (3 x 10(-7) M), to 51% by indomethacin (3 x 10(-6) M) and to 26% by N6-cyclopentyladenosine (10(-7) M), but was not affected by AA-861 (3 x 10(-6) M) or CP-96,345 (3 x 10(-7) M). In the three types of preparations, the dose-response curves for acetylcholine were alike with similar EC50s. These results suggest that the tone of longitudinal muscle was mainly induced due to neural activity in the myenteric plexus of guinea pig ileum and that sensitivity to acetylcholine was not affected by the neural activity.

Mechanism of tachyphylaxis on the inhibitory effect of manganese on agonist-induced contractions in the isolated vas deferens of the guinea pig

In the isolated vas deferens of the guinea pig, the inhibitory effect of manganese (Mn2+) on contractions induced by norepinephrine decreased when the contractions were induced repeatedly in the presence of Mn2+. This phenomenon, "tachyphylaxis" to the inhibitory effect of Mn2+, was minimally observed when contractions were induced by acetylcholine. Contractions induced by acetylcholine as well as by norepinephrine in a Mn(2+)-free medium were augmented in preparations in which manganese had accumulated intracellularly by repetitive applications of high potassium in the presence of Mn2+. The magnitudes of their augmentation were dependent on the manganese contents of the preparations. The augmented contractions were remarkably resistant to the inhibitory effect of Mn2+ applied to the medium. These results suggest that intracellular manganese augments the contractions and this augmentation results in an apparent decrease in the inhibitory effect of Mn2+ in the medium.

Tachykinin-induced contractions in the circular muscle of guinea pig ileum

Actions of substance P (SP, 10(-9) to 10(-6) M), neurokinin A (NKA, 10(-9) to 10(-6) M) and neurokinin B (NKB, 10(-10) to 10(-6) M) in the circular muscle of guinea pig ileum were investigated in segment and strip preparations, in which methacholine produced similar contractions. In the segment preparations, three tachykinins produced repeatedly occurring twitch-like contractions. Their efficacies were similar with the same maximal contractions, but their potencies were different (NKB > NKA = SP). Latency (38 sec) was observed before the initiation of contractions in response to NKA, but not to SP or NKB. Atropine (10(-6) M) and tetrodotoxin (3 x 10(-7) M) did not affect NKA-induced contractions, but inhibited SP- and NKB-induced contractions; the dose-response curves for SP and NKB were rightwardly shifted by atropine. The treatment with atropine brought out latency in the responses for NKB. In the strip preparations, SP did not substantially induce concentrations, but NKA and NKB produced twitch-like contractions after latent periods of 28 and 36 sec, respectively. The efficacy of NKA was similar to that in segment preparations, while that of NKB was much lower in strip preparations. Unlike in segment preparations, atropine did not inhibit contractions induced by the two tachykinins in strip preparations. These results suggest that tachykinins induce contractions through myogenic and neurogenic mechanisms, the latter of which may be inoperative in strip preparations.

Neurogenic "off" contractions are mediated by NK2-receptors in the circular muscle of guinea pig ileum

In guinea pig ileal circular muscle, electrical stimulations by a train of 10-100 pulses (0.05-msec duration, 10 Hz) produced tetrodotoxin-sensitive "off" contractions that were initiated upon the termination of stimulations. Atropine at 10(-6) M did not inhibit the "off" contractions. FK224 at 10(-5) M, a dual antagonist for NK1- and NK2-receptors, but not 10(-7) M CP-96,345, an antagonist for NK1-receptors, almost abolished the "off" contractions in the presence of atropine. These results suggest that the neurogenic "off" contraction was mediated mainly by NK2-receptors in the circular muscle of guinea pig ileum.

Production of nonstructural proteins of hepatitis C virus requires a putative viral protease encoded by NS3

Hepatitis C virus (HCV) is a positive strand RNA virus with certain similarity to flaviviruses and pestiviruses. To examine the processing and possible assembly of HCV proteins, we constructed a recombinant vaccinia virus that expresses a full-length genomic RNA, infected chimp liver cells with the virus, and analyzed HCV-related protein products by immunofluorescent antibody staining and Western blot detection with mouse monoclonal antibodies. The putative core, envelope, and NS1 and NS3 proteins that yielded from this recombinant were 22, 32, 53 to 58, and 65 kDa in size, respectively. The NS4 protein was unexpectedly small, with an estimated molecular weight of 7 kDa, and the NS5 protein was found to be further cleaved into 52-kDa NS5a and 58-kDa NS5b proteins, the latter of which contains a hallmark of RNA replicase. A point mutation in the putative protease domain of NS3 resulted in a failure in the production of NS3, NS4, NS5a, and NS5b, but coexpression of NS3 restored the proper processing of these proteins, demonstrating that NS3, the putative viral protease, is essential for the production of these nonstructural proteins. Thus, HCV strikingly resembles pestiviruses in the size and the processing mode of the nonstructural proteins, particularly NS4 and NS5.

Role of nitric oxide in the peristalsis in the isolated guinea-pig ileum

The role of nitric oxide in peristalsis was studied by using NG-nitro-L-arginine, an inhibitor of the biosynthesis of nitric oxide, in the isolated guinea-pig ileum. Constant peristalsis was cyclically induced by distending the ileal wall with intraluminal solution infused at a constant rate. NG-Nitro-L-arginine (10(-6) to 10(-4) M) dose dependently increased the frequency of peristalsis. This effect of NG-nitro-L-arginine was almost hindered by pretreating the ileum with 10(-3) M L-arginine, but not D-arginine. Nitroprusside (5 X 10(-7) M) reversed the frequency increase. In the presence of NG-nitro-L-arginine, peristaltic propulsion occurred at a smaller distension of the ileal wall and the ileum constricted to a smaller diameter at the completion of propulsion. The rate of shortening of longitudinal muscle during distension was raised by NG-nitro-L-arginine, although the peak magnitudes were not changed. Consistent with these effects of NG-nitro-L-arginine on peristalsis, NG-nitro-L-arginine at 10(-5) M increased the contractions of circular muscle in response to electrical field stimulation, but not those of longitudinal muscle. These results suggest that endogenous nitric oxide modulates peristalsis by limiting the contractile activity of the circular muscle of the guinea-pig ileum.

Stimulatory effects of HSR-803 on ileal motor activity

Stimulatory effects of HSR-803 on intestinal motor activity in vitro were studied in guinea pig ileum. HSR-803 (1 x 10(-6)-1 x 10(-4) M) increased the amplitude of longitudinal muscle contractions and increased the frequency of peristalsis in isolated segments of guinea pig ileum. The stimulatory effect in amplitude and not frequency was abolished by 1 x 10(-6) M atropine. In the Magnus method with ileal segments, HSR-803 (1 x 10(-7) - 1 x 10(-4) M) produced contractions concentration-dependently, which were inhibited by atropine (1 x 10(-8) and 3 x 10(-8) M) and 3 x 10(-7) M tetrodotoxin (TTX). In the [3H]-quinuclidinyl benzilate (QNB) binding experiment with ileal smooth muscle, HSR-803 had low affinity for acetylcholine (ACh) receptors (pKi = 4.47 +/- 0.04). In addition, HSR-803 failed to increase the spontaneous release and the electrical stimulation-induced [3H]ACh release in ileal smooth muscle. On the other hand, HSR-803 (1 x 10(-5) M) enhanced contractions induced by ACh, but had no effect on contractions induced by carbachol, which is not hydrolyzed by acetylcholinesterase (AChE). In conclusion, HSR-803 stimulated ileal motor activity. However, HSR-803 had low affinity for ACh receptors and had no influence on ACh release. It is likely that HSR-803 stimulated motor activity mainly due to prevention of ACh hydrolysis.

[The mechanism of glucose intolerance in patients with Graves' disease]

To investigate the mechanism of glucose intolerance in patients with Graves' disease, a 2-hour oral glucose tolerance test and euglycemic glucose clamp study using Biostator were performed in patients with Graves' disease and control subjects. 80 per cent of the patients showed impaired glucose tolerance. Insulinogenic index in the patients with borderline or diabetic glucose response was lower than that in subjects with normal glucose response. Insulinogenic index was inversely correlated with sigma PG during the test. Despite normal basal plasma glucose concentrations, basal plasma insulin levels in the patients with Graves' disease were higher than in the controls. Using the euglycemic glucose clamp technique, the glucose utilization rate (M value), the metabolic clearance rate of glucose (MCRG) and the insulin sensitivity index (M/I x 100) in the patients with Graves' disease were lower than in the controls. After treatment with antithyroid drug in 3 patients, glucose tolerance completely normalized, and there was a significant increase in the M value and the MCRG and a significant decrease in the metabolic clearance rate of insulin (MCRI) compared to the values before treatment. In the patients with Graves' disease, basal serum glucagon levels were higher than in the controls, and glucagon suppression during insulin infusion was found to be decreased. From these data, it is concluded that the decrease in glucose tolerance in patients with Graves' disease can be explained by 1) the impairment of early insulin release response to rapid intestinal glucose absorption, 2) increased insulin metabolic clearance and 3) hyperglucagonemia.

Evidence that stretch receptors for peristalsis are located in the mucosal layer of the guinea pig ileum

Location of stretch receptors triggering the peristalsis was investigated in the isolated guinea pig ileum. Peristalsis was cyclically induced by perfusing the lumen with Krebs solution flowing at a constant rate. Peristalsis was promptly abolished by serosally applied 3 x 10(-7) M tetrodotoxin, 10(-4) M lidocaine, 10(-6) M morphine or 10(-5) M nicotine, confirming the claim that peristalsis was neurally regulated by the myenteric plexus. Intraluminal application of 3 x 10(-7) M tetrodotoxin not only blocked the peristalsis, but also inhibited the contractions of the longitudinal muscle elicited by transmural stimulation or 10(-4) M nicotine by the same extent as those by serosal tetrodotoxin, suggesting that the blockade of peristalsis was due to the tetrodotoxin infiltrating into the muscle layer. In contrast, intraluminal application of 0.1% glutaraldehyde or perfusing the lumen with the low NaCl (20 mM)-containing Krebs solution abolished the peristalsis without critically inhibiting the neurogenic contractions of the longitudinal muscle, indicating that the blockade of peristalsis by these intraluminal treatments was ascribed to the actions on the mucosal layer. These results may imply that stretch receptors are located in the mucosal layer of the guinea pig ileum, and the impairment of the functions of these receptors by the intraluminal treatments leads to the blockade of the peristalsis.

[Difference of acute ketone body metabolism between insulin-dependent diabetic and non-insulin-dependent diabetic individuals]

The difference in the acute metabolic change in ketone bodies between patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM) was investigated in this study. The subjects employed were 7 patients with IDDM losing residual insulin secretion and 7 patients with NIDDM matched to the former patients for age, body mass index, duration of diabetes, daily insulin dosage, fasting plasma glucose and HbA1c. Blood samples were drawn at 3A.M. and 7A.M. on the same day, and plasma glucose, acetoacetic acid (AcAc), 3-beta-hydroxybutylic acid (3-OHBA), free fatty acid (FFA), glycerol, cortisol and growth hormone (GH) concentrations were determined. Plasma total ketone bodies (AcAc and 3-OHBA), 3-OHBA and FFA concentrations at 7A.M. were significantly higher in the patients with IDDM than in those with NIDDM (p < 0.05), while there were no significant differences in any other parameters at 3A.M. between the patients with IDDM and those with NIDDM. The ratios of 7A.M. value/3A.M. value of total ketone bodies, AcAc and 3-OHBA concentrations were also more significantly elevated in the patients with IDDM than in those with NIDDM. It was observed that the ratio of 3-OHBA was more than 2.0 in all of the patients with IDDM and less than 2.0 in all of the patients with NIDDM, the difference being significant with p < 0.001.(ABSTRACT TRUNCATED AT 250 WORDS)

[The possibility of hereditary factors in the susceptibility to diabetic nephropathy in NIDDM]

Diabetic nephropathy is the most important complication of diabetes, because it is a major cause of morbidity and mortality for diabetic subjects. Since not all subjects with diabetes are at risk of developing this complication, we conducted a study to determine if heredity might be a possible risk factor for diabetic nephropathy in non-insulin dependent diabetes. Twenty-one factors including inheritance of nephropathy and hypertension were investigated in 109 individuals with NIDDM: 50 patients without proteinuria (Group I), 20 patients with intermittent proteinuria (Group II), and 39 patients with continuous proteinuria (Group III) matched for age and duration of diabetes. Of those patients, 55 patients with inheritance of diabetes were also divided into three groups: 29 patients without proteinuria (Group I), 9 patients with intermittent proteinuria (Group II), and 17 patients with continuous proteinuria (Group III). Individuals in Groups II and III has significantly higher frequency of inheritance of diabetic nephropathy than those in Group I, and also individuals with inheritance of diabetic nephropathy had significantly higher frequency of diabetic nephropathy than those without it. Frequency of hypertension, retinopathy and body mass index in the past were significantly higher in subjects in Groups II or Group III than in those in Group I. There were no significant differences between subjects in Groups II and III. These findings suggest that susceptibility to diabetic nephropathy in NIDDM may be hereditary, although hypertension and obesity may also be important risk factors for diabetic nephropathy.

Effects of CP-96,345, a novel non-peptide antagonist of NK1 receptor, on the peristalsis in isolated guinea pig ileum

CP-96,345, a novel non-peptide antagonist of the NK1 receptor, at 10(-8)-10(-6) M decreased the frequency of peristalsis and reduced peristalsis-associated longitudinal muscle contractions in isolated guinea pig ileum. In the presence of 10(-6) M CP-96,345, further addition of 10(-6) M atropine blocked the peristalsis. When 10(-6) M atropine was first applied, more than half of the preparations developed atropine-resistant peristalsis. CP-96,345 at 10(-6) M blocked the atropine-resistant peristalsis. These results are consistent with the view that substance P is involved in the peristalsis in guinea pig ileum.

Inhibitory effect of inaperisone hydrochloride (inaperisone), a new centrally acting muscle relaxant, on the micturition reflex

We examined the effects of inaperisone hydrochloride (inaperisone), a new centrally acting muscle relaxant, on bladder function in anesthetized rats and isolated rat tissues. We also investigated its mechanism of action. When a balloon inserted into the bladder was expanded, rhythmic bladder contractions were observed; inaperisone (4 mg/kg i.v.) abolished these contractions, in both normal and decerebrated rats. The bladder tonus or bladder contraction induced by peripheral stimulation of the pelvic nerve was barely inhibited by inaperisone (4 mg/kg i.v.), but this dose of inaperisone abolished the efferent discharge from the pelvic nerve that accompanied the rhythmic bladder contractions. The doses of intracerebroventricularly (i.c.v.) and intrathecally injected inaperisone which abolished the rhythmic bladder contractions were 10 and 100 micrograms, respectively. The inhibitory effects of inaperisone (4 mg/kg i.v.) were not diminished by naloxone (1 mg/kg i.v.) or by bicuculline (0.5 mg/kg i.v.), but were diminished by phaclofen (30 mg/kg i.v. or 300 micrograms i.c.v.). The specific binding of [3H]baclofen to rat brain synaptosomal membranes was barely inhibited by inaperisone (up to 1 mM). From these results, it is speculated that, among other possible mechanisms, inaperisone inhibits the micturition reflex by acting indirectly on GABAB receptors in the brainstem.

Tachyphylaxis to the inhibitory effect of manganese on potassium-induced contractions in the isolated vas deferens of the guinea pig

In the isolated vas deferens of the guinea pig, the inhibitory effects of manganese (Mn2+) on the contractions induced by potassium (K+) were decreased when the contractions were induced repeatedly in the presence of Mn2+. This phenomenon appeared to be tachyphylaxis to the inhibitory effects of Mn2+. After the repetitive application of K+ with Mn2+, the phasic component of K(+)-induced contraction was restored, while the tonic component of this contraction and resting tone were augmented by the deprivation of extracellular Mn2+. When Mn2+ was applied during the tonic component of the K(+)-induced contraction, the phasic component of the next contraction induced by K+ in the absence of Mn2+ was slightly inhibited and the tonic component of the contraction was potentiated. When extracellular calcium concentration was increased, the inhibitory effect of Mn2+ on K(+)-induced contractions was reduced, while the tachyphylaxis to Mn2+ also appeared. Under this condition, the resting tone was markedly increased when the K(+)-induced contraction was repeated in the presence of Mn2+. In the calcium-free medium containing Mn2+, although K+ caused slow and monophasic contractions, the magnitude of the contractions was much smaller than that of the contractions induced in the normal medium containing Mn2+. These results suggest that the tachyphylaxis was not produced by the decrement of the inhibitory effects of Mn2+ on the contractions but by the augmenting effects of intracellularly accumulated Mn2+ and that these augmenting effects of Mn2+ are not due to the direct action on the contractile proteins but due to the indirect action of Mn2+ which increased the availability of Ca2+.

Effects of mazindol on the contractions in the rat vas deferens

Effects of mazindol on the contraction induced by nerve stimulation and agonist drugs were investigated to examine the inhibition of catecholamine uptake by mazindol in the vas deferens. Mazindol at 10(-9)-10(-7) M potentiated a single electrical pulse-elicited neurogenic contraction which consisted of a twitch and phasic contraction. This potentiation was almost completely antagonized by prazosin. Mazindol leftwardly shifted the dose-response curve to norepinephrine in a dose-dependent manner; the dose-ratio was 6.2-fold and 83.2-fold at 10(-9) M and 10(-7) M mazindol, respectively. The dose-response curves to dopamine and methacholine were also slightly shifted by mazindol. In the dibenamine-treated vas deferens, mazindol did not affect the dose-response curve to methacholine. These results suggest that mazindol potently inhibits the norepinephrine uptake without acting on the smooth muscle cells in the rat vas deferens.

Effects of ryanodine and nifedipine on contractions induced by norepinephrine, acetylcholine, and potassium in the isolated vas deferens of the guinea pig

In the present study we tried to determine the relative contributions of sarcoplasmic reticulum (SR) calcium release and gated calcium entry through voltage-dependent calcium-channels (VDC) to the contractions induced by norepinephrine (NE, 10 microM) and acetylcholine (ACh, 10 microM) in the vas deferens of the guinea pig. NE and ACh at 10 microM caused contractions composed of three phases: a prephasic, a phasic and a tonic component. Nifedipine strongly inhibited the contractions induced by potassium (K, 100 mM) and abolished phasic components of the contractions induced by NE or ACh. However, the tonic components of NE- or ACh-induced contractions were slightly attenuated by nifedipine. Pretreatment with ryanodine in combination with caffeine attenuated prephasic and tonic components of the contractions induced by NE and ACh in a dose-dependent manner. The inhibitory effects of ryanodine and caffeine on the phasic component of NE-induced contractions were divided into two types: 1) abolishment of the phasic contractions and 2) a delayed appearance of the phasic contractions without attenuation of magnitude. However, ryanodine with caffeine minimally affected phasic component by ACh- and K-induced contractions. Ryanodine pretreatment in combination with NE, ACh or K had no effect on the contractions induced by each agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

The uptake of manganese induced by agonists in the isolated vas deferens of the guinea pig

The uptake of manganese (Mn) induced by 100 mM potassium (K), 10 microM norepinephrine (NE) or 10 microM acetylcholine (ACh) was measured by atomic absorption spectroscopy in isolated vas deferens of the guinea pig. The agonists at these concentrations caused the maximal contraction of the vas deferens. The contents of Mn were increased with the repetitive treatments of Mn with K and were not significantly decreased after 1 h washing. The uptake of Mn was also stimulated by NE and ACh. The stimulation of uptake of Mn by K was the most potent while that by ACh was the smallest. The uptake of Mn was enhanced by elimination of Ca from the medium, while inhibited by the higher concentration of external Ca and by 2.1 microM diltiazem. The time course of K-induced Mn uptake was biphasic: an initial faster phase and a following slower phase of accumulation. The extents of increments of the Mn contents were dependent on the order of the applications of K and Mn: the increments became smaller in the following order, 1) when Mn was applied prior to K, 2) Mn was applied simultaneously with K, 3) Mn was applied after K. These results suggested that superficially bound Mn penetrates into the smooth muscle cells of vas deferens during the stimulation by agonists through the voltage-dependent calcium-channel (VDC) and that intracellular Mn was hardly extruded. It was also suggested that the degree of activation of VDC, through which Mn can enter the cells, was in the following order, K greater than NE greater than ACh. These results were consistent with our previous report about the dual effects of Mn: the inhibition and potentiation of contractions. It was also suggested that Mn may be a useful tool as a Ca analogue because Mn can penetrate into cells through VDC and, once taken up into the cells, Mn is not readily extruded and remains in the cells even after extracellular Mn is washed away.

Detrusor hyperreflexia induced by intravesical instillation of xylene in conscious rats

Intravesical instillation of xylene (30-50%) produced detrusor hyperreflexia characterized by a decrease in both the bladder capacity (time to micturition in the cystometrogram) and the urine volume in conscious rats placed in a restraining cage. At this time, the bladder tissue showed evidence of experimental cystitis with degradation of the epithelium and edema and hemorrhage in the submucosa, and a slight increase in the content of prostaglandin E2, which stimulated directly and/or indirectly capsaicin-sensitive sensory fibers. In addition, the bladder exhibited high amplitude spontaneous activity, but the bladder contractions induced by acetylcholine, substance P, prostaglandin E2 and capsaicin were not changed following intravesical instillation of xylene. In these hyperreflexic rats, atropine suppressed the amplitude of the micturition contraction and morphine increased the bladder capacity at similar doses as in sham-treated rats, while thiopental and indomethacin increased the bladder capacity at lower doses than in sham-treated rats. These findings indicated that intravesical instillation of xylene had produced detrusor hyperreflexia in conscious rats, and that the detrusor hyperreflexia is thought to be a useful model for evaluating the effect of a newly-developed agent on bladder function.

Propranolol blocks cocaine-induced potentiation of the contraction in the smooth muscle of the rat vas deferens

In the smooth muscle of the rat vas deferens, 10(-5) M cocaine shifted the dose-response curve to norepinephrine to the left and enhanced the maximal contractions to norepinephrine and methacholine. Propranolol at 10(-4) M almost completely blocked these potentiating effects of cocaine. Sotalol or lidocaine at 10(-4) M did not block the potentiating action of cocaine. The cocaine-induced enhancement of the methacholine contraction and its blockade by propranolol was observed in the dibenamine-treated vas deferens. Propranolol also blocked the depolarization-induced enhancement of the methacholine contraction. Together with the previous study demonstrating the calcium-antagonist action for propranolol, these results suggest that propranolol blocks the cocaine-induced enhancement by inhibiting the calcium influx through the potential-dependent calcium channel in the rat vas deferens.

Bicarbonate-dependent action of Bay K 8644 in the smooth muscle of the rat vas deferens

Effects of Bay K 8644, partial depolarization with high potassium, and nifedipine on the dose-response curves of the rat vas deferens to norepinephrine, methacholine and KCI were investigated in HEPES-buffered physiological salt solution (PSS) with or without 20 mM sodium bicarbonate. In the bicarbonate-containing PSS, Bay K 8644 at 10(-6) M enhanced the maximal contractions in response to norepinephrine, methacholine and KCI by 31.4, 103.3 and 40.1%, respectively. In the bicarbonate-free PSS, where the maximal contractions induced by norepinephrine, methacholine and KCI were 77.5, 75.0 and 68.2% of those in the bicarbonate-containing PSS, respectively. Bay K 8644 did not enhance the maximal contractile response to any of the agonists, although the contractions induced by low concentrations of KCI were increased by Bay K 8644. Increasing the potassium concentration in the PSS from 6 to 20 mM enhanced the maximal contractions in response to norepinephrine and methacholine in the bicarbonate-containing PSS, whereas in the bicarbonate-free PSS, the treatment decreased the contractions. In the two PSSs, nifedipine similarly inhibited the contraction in response to either 10(-5) M norepinephrine or 68 mM KCI. These results suggest that bicarbonate ion modulates the function of the voltage-dependent calcium channel in the smooth muscle of the rat vas deferens.

Effects of various drugs on bladder function in conscious rats

In the present study, we attempted to evaluate the effects of various intravenous administered drugs, which had been shown to influence bladder function in anesthetized animals, on the cystometrogram in conscious rats placed in a restraining cage. Thiopental, diazepam, baclofen, clonidine and flavoxate, considered to act on the micturition center in the brain stem, hardly increased bladder capacity (time to micturition in cystometrogram) in conscious rats, but morphine, indomethacin and lidocaine, considered to act on the micturition center in the sacral cord or bladder mechanoreceptors, increased it. In a chronic conscious rat, histopathological findings show that the bladder tissue at 2 days after implantation of the catheter to the bladder showed experimental cystitis characterized by severe edema in the submucosa and an increase in prostaglandin E2 content, which is thought to stimulate directly and/or indirectly the capsaicin-sensitive sensory fiber in the afferent branch of the micturition reflex, and there was hyperreflexia characterized by decreases in both bladder capacity and urine volume. In conclusion, cystometrography in conscious rats placed in a restraining cage is thought to be a useful model for evaluating the true effect of a newly developed agent on bladder function.

Role of bicarbonate ion in the postjunctional action of cocaine in the smooth muscle of the rat vas deferens

In the HEPES-buffered physiological solution containing 20 mM bicarbonate ion, cocaine not only increased the sensitivity to norepinephrine but enhanced the maximal contractions to norepinephrine and methacholine in the rat vas deferens. Cocaine also potentiated the high potassium-induced contractions. In the solution without bicarbonate ion, such effects of cocaine were lost except for the sensitivity increase to norepinephrine. These results suggest that bicarbonate ion is crucial for the postjunctional stimulatory action of cocaine in the rat vas deferens.

Effects of calcium-entry modulators on the biphasic neurogenic contractions in the circular muscle of guinea pig vas deferens

Effects of nifedipine (10(-8)-10(-6) M), verapamil (10(-6)-3 x 10(-5) M) and Bay k 8644 (10(-7) M) on the contractions induced by transmural nerve stimulation or agonists were investigated in the circular smooth muscle of guinea pig vas deferens using a ring preparation. Transmural stimulation (20 Hz for 20 sec) produced biphasic contractions consisting of initial phasic and secondary tonic components. Nifedipine preferentially inhibited the tonic component and norepinephrine (NE)-induced contractions over the phasic component and beta, gamma-methylene ATP (mATP)-induced contractions. Nifedipine suppressed the enhancing effect of NE on the mATP-induced contractions. The tonic component and NE-induced contractions were inhibited by verapamil in a similar dose range. Verapamil slightly inhibited the phasic component, but rather enhanced mATP-induced contractions. Bay k 8644 slightly increased the phasic component and mATP-induced contractions in the presence of prazosin. Bay k 8644 slowed the relaxation of the tonic component, thereby prolonging the tonic component. Bay k 8644 also prolonged the duration of NE-induced contractions. These results, except for the contradictory effects of verapamil between the phasic component and mATP-induced contractions, are consistent with the claim that ATP and NE are responsible for the generation of phasic and tonic component, respectively, in the circular muscle of guinea pig vas deferens.

Studies on isolated smooth muscle cells. VIII. 45Ca-efflux from single smooth muscle cells isolated from taenia coli of guinea pig

45Ca-loaded single smooth muscle cells were prepared from taenia coli of guinea pig. The cells were perfused continuously with physiological salt solution on membrane filter with pore size of 12 microns and radioactivity in the effluent was determined. The 45Ca-efflux curves consisted of two straight lines in semilogarithmic figure representing loosely and tightly bound calcium compartments with half time of 1.87 +/- 0.27 and 6.78 +/- 0.43 min, respectively. The loosely bound calcium was supposed to be localized on plasma membrane. Size of the tightly bound 45Ca was dependent on period for calcium-depletion of the preparation prior to 45Ca-loading. The efflux was stimulated by acetylcholine and the stimulated efflux returned to the spontaneous efflux level instantly after removal of acetylcholine. This stimulation was abolished by atropine. Repetitive stimulation failed to increase 45Ca-efflux while the rate of the spontaneous 45Ca-efflux did not change significantly. These results suggested that, in taenia coli of guinea pig, at least three calcium compartments existed, loosely bound calcium, tightly bound calcium and more tightly bound calcium which can be released by acetylcholine, in addition to calcium in extracellular fluid. Advantages and disadvantages of using single smooth muscle cells for investigation of calcium movement and some technical improvement for determination of 45Ca-efflux from single cells were described.

Pharmacological studies on supersensitization. XI. Inhibitory effect of dibenamine on tripelennamine-N,N-dimethyl-N',N'-dibenzylethylenediamine- and N,N-dibenzyl-N', N'-dimethyl-1, 2-propanediamine-induced supersensitivity of isolated vas deferens of guinea pig

Effects of dibenamine on tripelennamine-, N,N-dimethyl-N',N'-dibenzylethylenediamine (DBED)- and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine (DBPD)-induced supersensitivity of isolated vas deferens of guinea pig were examined. Dibenamine attenuated the degree of tripelennamine- and DBED-induced increase in sensitivity to acetylcholine and potassium in standard Tyrode solution, but did not affect the degree of DBPD-induced increase in sensitivity to acetylcholine. Dibenamine diminished the degree of tripelennamine-induced increase, but did not affect the degree of DBED-induced increase, in maximum response to Ca2+ of partially depolarized vas deferens. Dibenamine diminished the degree of tripelennamine- and DBED-induced augmentation of potassium-contraction in Ca2+-free Tyrode solution, but did not affect that of acetylcholine-contraction. These results suggest that dibenamine prevent tripelennamine- and DBED-induced increase in Ca2+-influx (including extracellular Ca2+-superficial Ca2+ exchange) induced by acetylcholine and potassium. It is also suggested that DBPD potentiates acetylcholine-contraction by dibenamine-insensitive mechanisms.

Pharmacological studies on supersensitization. XII. Inhibitory effect of reserpine on tripelennamine-, N,N-dimethyl-N',N'-dibenzylethylenediamine- and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine-induced supersensitivity of isolated vas deferens of guinea pig to acetylcholine

Effects of tripelennamine, N,N-dimethyl-N',N'-dibenzylethylenediamine (DBED) and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine (DBPD) on the isotonic contractions of isolated vas deferens of intact and reserpinized guinea pigs to acetylcholine were examined. Increase in sensitivity to acetylcholine induced by tripelennamine, DBED and DBPD was attenuated remarkably by reserpine. Tripelennamine- and DBED-induced increases in Ca2+-contractions were not affected by reserpine. Acetylcholine-contractions in Ca2+-free Tyrode solution were inhibited by reserpine, but K+-contractions in Ca2+-free Tyrode solution were not affected by reserpine. Tripelennamine- and DBED-induced increases in acetylcholine- and K+-contractions in Ca2+-free Tyrode solution were attenuated or abolished by reserpine. DBPD decreased cholinesterase activity of vas deferens of guinea pig, but DBED did not. These results suggest that, although the Ca2+-storage site utilized for acetylcholine-contraction is different from that for K+-contraction, tripelennamine- and DBED-induced increase in Ca2+-release from superficial Ca2+-binding sites induced by acetylcholine and K+ is inhibited by reserpine. It is also estimated that DBPD-induced supersensitivity to acetylcholine might be due to the inhibition of cholinesterase activity. However, the mechanism of inhibition of DBPD-induced supersensitivity by reserpine remained obscure.

Pharmacological studies on supersensitization. X. Effect of tripelennamine, N,N-dimethyl-N',N'-dibenzylethylenediamine and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine on the utilization of calcium in acetylcholine-induced contraction of isolated vas deferens of guinea pig

Effects of tripelennamine, N,N-dimethyl-N',N'-dibenzylethylenediamine (DBED) and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine (DBPD) on the isotonic contractions of isolated vas deferens of guinea pig were examined. Tripelennamine and DBED potentiated the contractile responses to acetylcholine and potassium chloride in Ca2+-free Tyrode solution. DBPD potentiated the contractile responses to lower concentrations of acetylcholine in Ca2+-free Tyrode solution, but did not affect contractions induced by potassium and higher concentrations of acetylcholine in Ca2+-free Tyrode solution. In depolarized vas deferens, tripelennamine and DBED augmented the maximum response to Ca2+, while DBPD did not affect the maximum response to Ca2+ and decrease the sensitivity to Ca2+. The contractile responses to acetylcholine in standard Tyrode solution were attenuated by lanthanum chloride and the residual contractions were not affected by tripelennamine, DBED and DBPD or decreased by DBPD. The contractile responses to potassium chloride were completely abolished by lanthanum chloride. The half-time of decrease in acetylcholine-contraction in Ca2+-free Tyrode solution was significantly different from that of potassium-contraction in Ca2+-free Tyrode solution. The contractile response of the glycerinated muscle piece of vas deferens to calcium chloride was potentiated by DBED, but was not affected by tripelennamine and DBPD. These results suggest that tripelennamine and DBED facilitate nonselectively the transmembrane influx of calcium from extracellular fluid and superficial calcium-binding sites. In addition, DBED increases the sensitivity of contractile element to cytoplasmic free calcium ion. DBPD potentiates the contractile response without affecting the transmembrane mobilization of Ca2+ induced by excitation of cell membrane.

Pharmacological studies on supersensitization. IX. Non-specific supersensitivity of vas deferens of guinea pig induced by tripelennamine, N,N-dimethyl-N',N'-dibenzylethylenediamine and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine

Effects of tripelennamine, N,N-dimethyl-N',N'-dibenzylethylenediamine (DBED) and N,N-dibenzyl-N',N'-dimethyl-1,2-propanediamine (DBPD) on the isotonic contractions of isolated vas deferens of guinea pig were examined. These ethylenediamines, except DBPD, induced slight but significant increase in sensitivity of vas deferens to K+. Tripelennamine induced dose-dependent potentiation to epinephrine and norepinephrine, but tripelennamine-induced augmentation of acetylcholine-contractions was weak and dose-independent. DBED potentiated both catecholamines and acetylcholine in a dose-dependent way and in the same degree. The degree of DBPD-induced augmentation of epinephrine- and norepinephrine-induced contractions was dose-independent and much weaker than that of acetylcholine-contractions. Tripelennamine and DBED did not affect the contractile response to tyramine, while DBPD potentiated the contractile response to tyramine. These results suggest the following possibilities: 1) tripelennamine affects both amine uptake mechanism and beyond receptor mechanism of contractile processes and induced supersensitivity of various stimulants. 2) DBED affects mainly beyond receptor mechanism of contractile processes and augments the contractile responses to various stimulants. 3) The mechanism of DBPD-induced supersensitivity remained obscure, but the inhibition of the metabolic degradation of stimulants was proposed as one of the possible mechanism of supersensitization.