Successful cochlear implantation in a patient with mitochondrial hearing loss and m.625G>A transition.

OBJECTIVE: We present a patient with mitochondrial hearing loss and a novel mitochondrial DNA transition, who underwent successful cochlear implantation. CASE REPORT: An 11-year-old girl showed epilepsy and progressive hearing loss. Despite the use of hearing aids, she gradually lost her remaining hearing ability. Laboratory data revealed elevated lactate levels, indicating mitochondrial dysfunction. Magnetic resonance imaging showed diffuse, mild brain atrophy. Cochlear implantation was performed, and the patient's hearing ability was markedly improved. Whole mitochondrial DNA genome analysis revealed a novel heteroplasmic mitochondrial 625G>A transition in the transfer RNA gene for phenylalanine. This transition was not detected in blood DNA from the patient's mother and healthy controls. Mitochondrial respiratory chain activities in muscle were predominantly decreased in complex III. CONCLUSION: This case indicates that cochlear implantation can be a valuable therapeutic option for patients with mitochondrial syndromic hearing loss.

MERRF/MELAS overlap syndrome: a double pathogenic mutation in mitochondrial tRNA genes.

BACKGROUND: Myoclonic epilepsy with ragged-red fibres (MERRF) and mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are established phenotypes of mitochondrial encephalomyopathy. The m.8356T>C transition in the mitochondrial tRNA(Lys) gene is a pathogenic mutations of MERRF. The m.3243A>G transition in the mitochondrial tRNA(Leu) gene is detected in most MELAS patients. Although previous analyses of double mutations in mitochondrial DNA (mtDNA) were useful for discussing their nature, many unsolved questions remain. OBJECTIVE: To describe the clinical and genetic features of a family with the above mtDNA double-point mutations and discuss the role of double mtDNA mutations in diverse clinical features in the family. PATIENTS AND METHODS: The proband was a 23-year-old woman with MERRF harbouring m.8356T>C and m.3243A>G transitions in mitochondrial tRNA genes. We assessed clinical aspects of her and those of her three relatives and performed mutation analyses on their mtDNA. RESULTS: Phenotypes of the four patients were MERRF, MERRF/MELAS overlap syndrome and asymptomatic carrier. We hypothesise that the course of the phenotype of this family begins with MERRF and is followed by MELAS. This double mutation was heteroplasmic in blood of all four patients but with different rates in each patient, while m.8356T>C appeared homoplasmic and m.3243A>G was heteroplasmic in muscle of the two examined cases. No other mutations were detected in the total mtDNA sequence in this family. CONCLUSIONS: This is the first reported case of a double-point mutation in mtDNA, both of which were heteroplasmic and pathogenic for the established phenotypes.

Pharmacological effect of amezinium on urethra and bladder of rabbits.

The pharmacological effect of amezinium on the urethra and bladder of rabbits was investigated. Amezinium produced concentration-dependent contractions in isolated urethral strips. The maximum response was approximately 30% of that caused by norepinephrine (NE). The concentration-response curve of NE was shifted to the left by amezinium. Moreover, amezinium enhanced the relaxative effect of NE on carbachol-induced contractions in isolated bladder strips. In anesthetized rabbits, amezinium significantly increased the intraurethral pressure (IUP) but produced only slight increases in mean blood pressure (MBP). Pre-treatment with amezinium ehhanced NE-induced increases in IUP index and MBP. The enhancing effect on the IUP index lasted much longer than that on MBP. In a stress incontinence model amezinium significantly inhibited the incontinence after an i.v. infusion of a low dose of NE. This effect was antagonized by pre-treatment with prazosin. These results suggest that amezinium may produce an excellent effect for stress incontinence, especially mixed, without severe adverse events such as sudden hypertension.

Urodynamics in acetone-induced cystitis of anesthetized rats.

We examined the bladder function of cystitis models induced by intravesical acetone instillation in urethane-anesthetized rats. Acetone (0.35 ml) at 10, 30, or 50% concentration or deionized water (sham-treatment) was instilled into the bladder via the cannula which was inserted into the lumen. Acetone was withdrawn 90 sec after instillation and the bladder lumen was washed with saline after 15 min. One hour later, the cystometrogram induced by transvesical infusion of saline (3.3 ml/hr) was measured. During cystometrography of normal (non-treated) or sham-treated group, the time required to cause micturition, reflecting bladder capacity, was 9.6 +/- 0.9 (n = 7) or 10.0 +/- 0.8 min (n = 6), respectively. In the 10% acetone-treated group, the bladder capacity was similar to that in the normal or sham group. In the 30% acetone group, the time to micturition was 4.4 +/- 0.4 min (n = 7), indicating decreased bladder capacity, although the micturition pressure and the threshold pressure were not significantly different from those in the normal or sham group. However, in the 50% acetone group, the micturition reflex disappeared. In isolated rat bladder strips, contractile responses to carbachol or electrical field stimulation in the sham and 30% acetone group were similar. While, both responses in isolated strips from the 50% acetone group were reduced. The degree of damage from degeneration and desquamation of epithelium and hemorrhage in the bladder tissue from the 30% acetone group was less prominent than in the 50% acetone group. Additionally, some tissue from the 50% acetone group showed degeneration of muscle layer. The effects of three drugs were investigated in the 30% acetone group which showed increased urinary frequency. Baclofen (100 microg/kg, i.v.) and morphine (100 microg/kg, i.v.) increased significantly the bladder capacity and the threshold pressure. Atropine (10 microg/kg, i.v.) decreased the micturition pressure. These results suggest that cystitis models induced by intravesical instillation of 30% acetone may be valuable for evaluating drugs for the treatment of urinary frequency.

Effects of monatepil maleate, a new Ca2+ channel antagonist with alpha1-adrenoceptor antagonistic activity, on cholesterol absorption and catabolism in high cholesterol diet-fed rabbits.

The mechanism of the prophylactic effect against hyperlipidemia by monatepil maleate was investigated in animal models. Monatepil maleate is an antihypertensive agent with Ca2+-channel antagonistic, alpha1-adrenergic receptor-blocking, and lipid peroxidation inhibitory activity. In high cholesterol diet-fed rabbits, monatepil maleate (30 mg/kg, p.o., once daily for 9 weeks) showed a prophylactic effect against increases in total cholesterol and beta-lipoprotein. Monatepil maleate significantly accelerated the clearance of radioactivity from the blood after intravenous injection of low-density lipoprotein (LDL) labeled with [1alpha,2alpha (n)-3H]cholesterol, increasing biliary excretion of [3H]-bile acids without modifying bile acid composition. Furthermore, monatepil maleate tended to inhibit the absorption of orally administered [1alpha,2alpha (n)-3H]cholesterol from the gastrointestinal tract in these rabbits. In Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model of hepatic LDL receptor deficiency, monatepil maleate (30 mg/kg, p.o., once daily for 6 months) did not suppress the increase in plasma lipids. These results suggest that the plasma lipid lowering effect of monatepil maleate requires the presence of hepatic LDL receptors. It is also suggested that monatepil maleate improves plasma lipid metabolism through two mechanisms: enhancement of clearance of plasma LDL, which may be mediated by up-regulation of hepatic LDL receptors, and acceleration of conversion of free cholesterol to bile acids in the liver.

Affinity of mosapride citrate, a new gastroprokinetic agent, for 5-HT4 receptors in guinea pig ileum.

We examined the binding affinity of mosapride citrate (mosapride) (4-amino-5-chloro-2-ethoxy-N-[[4-(4-fluorobenzyl)-2-morpholinyl]me thyl] benzamide citrate), a novel gastroprokinetic agent, for the 5-hydroxytryptamine (5-HT) 4 receptors in guinea pig ileum using a selective 5-HT4-receptor radioligand, [3H]GR113808. In membrane preparations from longitudinal muscle with myenteric plexus in guinea pig ileum, specific [3H]GR113808 binding revealed a single saturable site of high affinity (Kd=0.28 +/-0.02 nM, Bmax = 45+/- 3 fmol/mg protein). Mosapride and other 5-HT4-receptor agonists inhibited the specific binding of [3H]GR113808 in guinea pig ileum. The 5-HT4 agonists examined displayed the following inhibition potency order: BIMU-8 > cisapride > mosapride > renzapride > 5-HT > zacopride > metoclopramide. Mosapride exhibited monophasic inhibition of the specific [3H]GR113808 binding in the ileum (Ki value: 84.2 nM). The presence of mosapride (30 nM) significantly increased the Kd value to 0.44+/-0.05 nM in the Scatchard analysis of [3H]GR113808 binding. Bmax of [3H]GR113808, however, was not affected (48 +/-4 fmol/mg protein) by mosapride. As for the affinity of mosapride, the addition of GppNHp (100microM) slightly increased the Ki value to 104 nM. These results indicate that mosapride has an affinity for 5-HT4 receptors in guinea pig ileum in the radioligand binding study.

Post-treatment of transient focal cerebral ischemia in rats with the novel cerebrovascular-selective Ca2+ channel antagonist (+/-)-(E)-1-(3-fluoro-6,11-dihydrodibenz[b,e]-oxepine-11-yl)-4-(3-pheny l-2-propenyl)-piperazine dimaleate.

The efficacy of post-ischemic treatment with AJ-3941 ((+/-)-(E)-1-(3-fluoro-6,11-dihydrodibenz[b,e]-oxepine-11-yl )-4-(3-phenyl-2- propenyl)-piperazine dimaleate, CAS 143110-70-7), a cerebrovascular selective Ca2+ channel antagonist, on brain infarction induced by focal ischemia-reperfusion in rats was evaluated. Focal ischemia was induced by transient occlusion of middle cerebral artery (MCA) with a 3-0 nylon monofilament for 90 min. One day after MCA occlusion (MCAo), brain infarct size was determined by measuring 2,3,5-triphenyltetrazonium chloride-negative stained area of the serial brain sections. The development of cerebral infarction was observed in both regions of cortex and subcortex, such as striatum, caudatum, putamen, hippocampus and corpus callosum. Post-ischemic treatment with AJ-3941 (1 or 3 mg/kg p.o., 10 min and 3 h after the occlusion) significantly reduced the infarct size and volume in the ipsilateral hemisphere in a dose-dependent manner, compared to the solvent control. The reducing effect was observed mainly in the cortical region, and a significant reduction of the subcortical infarct volume was found at the higher dose (3 mg/kg). Post-ischemic treatment with the thromboxane A2 synthetase inhibitor, sodium ozagrel (150 micrograms/kg/min i.v. infusion, between 1 h and 24 h after the MCAo) did not reduce the infarct volume in the hemisphere after ischemia-reperfusion. AJ-3941 had only minimum effect on the elevation of body temperature during ischemia-reperfusion. These results indicate that post-ischemic treatment with AJ-3941 may ameliorate the brain injury after the transient focal cerebral ischemia, and they suggest that AJ-3941 has beneficial effects for treatment of ischemic cerebral damage, such as stroke.

Inhibitory effect of monatepil maleate on acyl-CoA:cholesterol acyltransferase activity in the liver of cholesterol-fed Japanese monkeys.

We have previously demonstrated that monatepil maleate, AJ-2615, a new calcium antagonist endowed with alpha1-adrenoceptor blocking property, has antiatherosclerotic and plasma lipid-lowering effects in Japanese monkeys fed on a cholesterol-rich diet. To clarify the mechanisms on plasma lipid-lowering action, we investigated the effect of monatepil maleate in these monkeys on hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activity. Both ACAT activity and esterified cholesterol content in the livers of monkeys fed on a cholesterol-rich diet for 6 months significantly increased about 7- and 16-fold, respectively, as compared with those in monkeys fed on a standard diet. Monatepil maleate (30 mg/kg/day for 6 months, orally) inhibited the increases of ACAT activity and esterified cholesterol content by 51% and 71%, respectively. In in vitro experiments, monatepil maleate inhibited ACAT activity in a concentration-dependent manner, whereas it did not affect 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity. A kinetic analysis revealed that monatepil maleate was a noncompetitive type inhibitor of ACAT. Hepatic ACAT activity was significantly correlated to hepatic esterified cholesterol content (r = 0.775, P < .0001), to plasma very low density lipoprotein (VLDL) content (r = 0.765, P < .0001) and to plasma total cholesterol content (r = 0.573, P < .005) in the monkeys. These results suggest that ACAT-inhibiting effect of monatepil maleate plays an important role in the reduction of hyperlipidemia.

Possible involvement of ATP-dependent K-channel related mechanisms in the antihypertensive and cough suppressant effects of the novel ACE inhibitor (2S, 3aS, 7aS)-1-(N2-nicotinoyl-L-lysyl-gamma-D-glutamyl)octahydro-1H- indole-2-carboxylic acid.

The antihypertensive and cough suppressant mechanisms of DU-1777 ((2S,3aS,7aS)-1-(N2-nicotinoyl-L-lsyl-gamma-D-glutamyl )octahydro-1H-indole-2 -carboxylic acid, CAS 116662-73-8), a new long-acting angiotensin-1-converting enzyme (ACE) inhibitor, were investigated in vivo and in vitro. The antihypertensive effects of DU-1777 at 10 mg/kg p.o. and cromakalim at 0.3 mg/kg p.o. were partially (about 60%) or fully antagonized by glibenclamide at 10 mg/kg i.v. in 2-kidney, 1-clip renal hypertensive rats (2K-1C RHR). The antihypertensive effects of a Ca blocker (nifedipine) and other ACE inhibitors (captopril, alacepril, enalapril, lisinopril, imidapril and quanapril) were not antagonized by glibenclamide. In deoxycorticosterone acetate-salt hypertensive rats (DOCA-HR), the antihypertensive effects of DU-1777 at 3-30 mg/kg p.o. were fully antagonized by glibenclamide. However, in vitro, DU-1777 (10(-6)-10(-3) mol/l) did not affect aortic ring contractions induced by high K (30 mmol/l). In guinea pig, citric acid induced cough was increased by ACE inhibitors, captopril, alacepril, enalapril and lisinopril (10 and 30 mg/kg p.o.). DU-1777 had a tendency to decrease citric acid induced cough and the effect was antagonized by glibenclamide. These results suggest that while DU-1777 itself does not open ATP-dependent K channel, it indirectly produces these effects through unknown mechanisms in vivo. Moreover, these effects contributed to the antihypertensive effect in DOCA-HR and cough suppressant effect in guinea pigs.

Cerebrovascular selectivity and vasospasmolytic action of the novel calcium antagonist (+/-)-(E)-1-(3-fluoro-6, 11-dihydrodibenz[b,e]oxepin-11-yl)-4-(3-phenyl-2-propenyl)-piperazine dimaleate in isolated cerebral arteries of the rabbit and dog.

The cerebrovascular selectivity and vasospasmolytic action of AJ-3941 ((+/-)-(E)-1-(3-fluoro-6, 11-dihydrodibenz[b,e]oxepin-11-yl)-4-(3-phenyl-2-propenyl)-p iperazine dimaleate. CAS 143110-70-7), a new calcium antagonist, were studied in isolated rabbit and dog arterial preparations. In rabbit arterial ring preparations, AJ-3941 dose-dependently inhibited the contractions of various arteries caused by high K(+)-depolarization (high K+) and prostaglandin F2 alpha (PG). The inhibitory potency of AJ-3941 varied in different arteries, in descending order as follows: high K+: basilar > coronary > femoral > renal > mesenteric artery, PG: basilar > coronary > > femoral and renal artery. The median inhibitory concentration (IC50) in the basilar artery was over 40 times lower than that in the mesenteric or femoral artery for which the weakest inhibition in the examined arteries was observed. This selective action of AJ-3941 for cerebral artery was also observed in the frontal and middle cerebral arteries of dogs. The selectivity for the rabbit basilar artery was higher than those of flunarizine and nicardipine. Additionally, the contractile response of the rabbit basilar artery induced by phorbol 12,13-dibutyrate (PDBu), an activator of protein kinase C (PKC), was greater than those of the arteries examined such as the coronary, femoral and mesenteric arteries. The response in the basilar artery was greatly reduced in Ca(2+)-free medium, while this was not the case in other arteries. AJ-3941 as well as H-7, an inhibitor of PKC, potently inhibited PDBu-induced contractile response in the basilar artery in the presence, but not in the absence of Ca2+ in the medium, whereas the existing calcium antagonists, diltiazem and nicardipine, did not inhibit the contractile response in both conditions. These results suggest that the PKC-dependent system which is mediated by influx of extracellular Ca2+ profoundly contributes to the contraction of the cerebral artery and that the cerebroselective-vasodilating effect of AJ-3941 may depend, at least partly, on the inhibition of the PKC-mediated contractile response. In rabbit basilar arteries, AJ-3941 caused a dose-dependent inhibition of the contraction induced by various vasospasmogens, such as endothelin-1 (ET), arachidonic acid, 15-hydroperoxy-eicosatetraenoic acid and the thromboxane A2-mimetic U-46619. Furthermore, when isolated basilar arteries of the dog were perfused intraluminally with AJ-3941 at the concentration that inhibits high K(+)- or PG-induced contraction in the rabbit basilar artery, AJ-3941 effectively antagonized the vasospasm induced by extraluminal application of PG or ET. However, when flunarizine, nicardipine, diltiazem or verapamil was used for intraluminal perfusion of the same preparations, none of these drugs exerted spasmolytic effect. These results indicate that AJ-3941 has cerebrovascular selective-vasospasmolytic action, and consequently is thought to be effective in cerebrovascular disorder such as vasospasm following subarachnoid hemorrhage.

Comparison of effect of mosapride citrate and existing 5-HT4 receptor agonists on gastrointestinal motility in vivo and in vitro.

Mosapride citrate is a new gastroprokinetic agent that enhances the upper GI motility by stimulating 5-hydroxytryptamine4 (5-HT4) receptors. The purpose of this study was to compare the effects of mosapride and the existing 5-HT4 receptor agonists on GI motility in conscious dogs and on various 5-HT4 receptor-mediated responses in vitro. In conscious dogs with force transducers implanted, mosapride (0.3-3 mg/kg i.v.) stimulated the antral motility without affecting the colonic motility. However, cisapride, zacopride and BIMU 8 (0. 1-1 mg/kg i.v.) stimulated both antral and colonic motility. The enhanced GI motility induced by mosapride or cisapride was antagonized by pretreatment with GR113808 (1 mg/kg bolus i.v., thereafter 1 mg/kg/hr infusion), a selective 5-HT4 receptor antagonist. In the receptor binding studies, mosapride inhibited [3H]-GR113808 binding to 5-HT4 receptor sites of guinea pig striatum with an IC50 value of 113 nM. In addition, mosapride caused relaxation of the carbachol-precontracted rat esophagus, enhanced the electrically evoked contractions of guinea pig ileum and evoked the contractions of guinea pig distal colon with EC50 values of 208, 73, and 3029 nM, respectively; this indicates that mosapride has a low affinity for colon than for the rest of the GI tract. In contrast, cisapride, zacopride or BIMU 8 had similar potencies in all preparations examined. In conclusion, these studies indicate that mosapride selectively stimulates upper GI motility in vivo and in vitro. These results also suggest heterogeneity of 5-HT4 receptors in the GI tract.

Alacepril, an angiotensin-converting enzyme inhibitor, prevents cerebral vasospasm in subarachnoid hemorrhage model in rats.

The effects of angiotensin-converting enzyme (ACE) inhibitors was investigated on the development of cerebral vasospasm and on the endothelium-dependent relaxation in the rat subarachnoid hemorrhage (SAH) model. Alacepril or enalapril was used as an ACE inhibitor with or without a thiol moiety in the structure. SAH rats or sham-operated rats were produced by the injection of homologous blood or artificial cerebrospinal fluid into the cisternal magna, respectively. In the SAH rat, cerebral vasospasm was observed at 24 h after blood injection. Acetylcholine (Ach)-induced relaxation in basilar arteries from SAH rats significantly decreased compared to that from sham-operated rats, although the relaxation induced by 3-morpholinosydnonimine, sodium nitroprusside or papaverine did not decrease. These results suggest that the endothelium cell function of basilar arteries in SAH rats is damaged. Alacepril prevented both the development of cerebral vasospasm and the suppression in the Ach-induced relaxation of basilar artery in SAH rats. However, enalapril did not prevent the suppression of Ach-induced relaxation in SAH rats, despite the tendency to prevent cerebral vasospasm. Therefore, it is suggested that the preventive effect of alacepril on cerebral vasospasm could be based on its protective effect on endothelium-dependent relaxation system.

Prevention by the new Ca2+ channel antagonist, AJ-3941, of loss of endothelium-dependent relaxation after subarachnoid hemorrhage in rats.

AJ-3941 ((+/-)-(E)-1-(3-fluoro-6,11-dihydrodibenz[b,e]-oxepine-11-yl ) -4-(3-phenyl-2-propenyl)-piperazine dimaleate; CAS No. 143110-70-7), a cerebrovascular-selective Ca2+ channel antagonist having anti-lipid peroxidative action, was reported to prevent cerebral vasospasm following subarachnoid hemorrhage in rats. The present study was undertaken to determine whether AJ-3941 protects the impairment of cerebroarterial endothelium-dependent relaxation which is concomitantly induced with cerebral vasospasm. Subarachnoid hemorrhage biphasically suppressed the response to acetylcholine in rat basilar artery, at 0.5 h (n = 4; P < 0.06) and 1 day (n = 5; P < 0.05) after subarachnoid hemorrhage. The reduction of the responses was correlated significantly to the degree of vasospasm determined angiographically. This reduction was accompanied by a 49% increase of arterial lipid peroxide contents. Endothelium-independent relaxation in subarachnoid hemorrhage rats was preserved in response to 3-morpholinosydnonimine, sodium nitroprusside and papaverine. AJ-3941 prevented (n = 6-8, P < 0.05) the suppression of the acetylcholine-induced response and the increase in lipid peroxide content in subarachnoid hemorrhage rats. These results suggest that AJ-3941 could exert its vasospasmolytic effect by preserving endothelial function through its anti-lipid peroxidative action, in addition to its inhibition of vasospasmogen-induced vasoconstriction related to intracellular Ca2+ mobilization.

Effect of (+/-)-(E)-1-(3-fluoro-6,11-dihydrodibenz[b,e]-oxepine-11 -yl)-4-(3-phenyl-2-propenyl)-piperazine dimaleate on cerebral vasospasm and impairment of cerebral circulation in subarachnoid hemorrhage model in rats.

A subarachnoid hemorrhage (SAH) model in rats was produced by the injection of homologous blood into the cisterna magna. Effects of AJ-3941 ((+/-)-(E)-1-(3-fluoro-6,11 -dihydrodibenz[b,e]-oxepine-11-yl)-4-(3-phenyl-2-propenyl)-p iperazine dimaleate, CAS 143110-70-7) on the development of cerebral vasospasm and the change of regional cerebral blood flow (rCBF) following SAH was investigated in this model. Cerebral vasospasm following SAH showed a biphasic pattern with an early phrase at 10 min and a late phrase on 1 day after blood injection. The physiological parameters (blood pressure, heart rate and blood gas contents) remained stable within the physiological range throughout the course of the experiment. AJ-3941 (0.01 mg/kg i.v. or 0.3 mg/kg p.o.) significantly prevented the development of late phase cerebral vasospasm. Cisternal injection of homologous blood significantly reduced rCBF immediately after the injection and the reduction lasted during the observation period (30 min). Reduction in rCBF after the injection of homologous blood was prevented by AJ-3941 (0.01 mg/kg i.v.). rCBF in AJ-3941-treated rats completely returned to the basal values after 30 min. The present suggest that AJ-3941 may be useful in the prevention of late spasm and in the improvement of cerebral circulation impaired with SAH.

Protective effect of the novel cerebrovascular-selective calcium antagonist (+/-)-(E)-1-(3-fluoro-6, 11-dihydrodibenz[b,e]-oxepine-11-yl)-4-(3-phenyl-2-propenyl)-piperazine dimaleate on ischemic brain damage after permanent middle cerebral artery occlusion in rats.

In this study the effect of post-ischemic treatment of AJ-3941 ((+/-)-(E)-1-(3-fluoro-6,11-dihydrodibenz [b,e]-oxepine-11-yl)-4-(3-phenyl-2-propenyl)-piperazine dimaleate, CAS 143110-70-7) a cerebrovascular-selective calcium antagonist, on brain infarction and edema in a rat model of focal cerebral ischemia with permanent middle cerebral artery occlusion (MCAo) was evaluated. Brain infarct size was determined at 24 h after MCAo by measuring 2,3,5-triphenyltetrazolium chloride-negative stained area of the serial brain sections. Post-ischemic treatment of AJ-3941 (3 mg/kg p.o.), 10 min and 3 h after the insult, significantly reduced brain infarct size by 44-80%, compared to vehicle control. The reducing effect was observed both in the cortical and subcortical regions. Three days after MCAo, contents of water and Na+ in the ipsilateral hemisphere significantly increased comparing with those in control rats. Post-ischemic treatment with AJ-3941 (3 and 10 mg/kg twice daily p.o. for 2 days) markedly inhibited the increase in water content and suppressed the increase in Na+ content. In the contralateral hemisphere, these contents showed no significant differences between vehicle-treated group and either control (non-operated) or AJ-3941-treated group. AJ-3941 had only minimum effect on body temperature and physiological parameters, such as blood pressure, blood gases and glucose, even when the maximum dose used (10 mg/kg) was repeatedly administered. These results indicate that post-ischemic treatment with AJ-3941 may ameliorate the brain infarction and edema after permanent focal cerebral ischemia, and they also suggest that AJ-3941 has a beneficial effect in the treatment of ischemic cerebral damage.

Involvement of dopamine D3 receptors in the area postrema in R(+)-7-OH-DPAT-induced emesis in the ferret.

We investigated the possible involvement of dopamine D3 receptors in R(+)-7-hydroxy-2-(N,N-di-n-propylamino)tetraline (R(+)-7-OH-DPAT)-induced emesis in the ferret. The R(+)enantiomer of 7-OH-DPAT (0.03-1 mg/kg, s.c.) caused emesis in a dose-dependent manner, whereas the S(-)enantiomer, even at 1 mg/kg s.c. failed to induce emesis. Quinpirole (0.1-1.0 mg/kg) and apomorphine (0.3 mg/kg, s.c. only) also elicited an emetic response. S(-)-Eticlopride, which has a high affinity for the dopamine D3 receptor, antagonized R(+)-7-OH-DPAT (0.3 mg/kg, s.c.)-induced emesis (ID50 1.4 micrograms/kg, s.c.). R(+)-7-OH-DPAT (0.1-1.0 microgram) administered into the 4th cerebral ventricle dose dependently induced emesis within 1 min of dosing in ferrets. Intracerebroventricularly administered S(-)-eticlopride (0.01-1 microgram) also inhibited the emesis induced by s.c. administration of R(+)-7-OH-DPAT. The emetic effect of R(+)-7-OH-DPAT was unaffected by abdominal vagotomy but was markedly reduced by ablation of the area postrema. These results suggest that dopamine D3 receptors in the area postrema play an important role in R(+)-7-OH-DPAT-induced emesis in the ferret.

Studies on calcium antagonistic and alpha 1-adrenergic receptor blocking activities of monatepil maleate, its metabolites and their enantiomers.

The calcium antagonistic and alpha 1-adrenergic receptor blocking activities of monatepil maleate (CAS 103377-41-9, (+/-)-N-(6,11-dihydrodibenzo [b, e] thiepin-11-yl) -4-(4-fluorophenyl)-1-piperazinebutanamide monomaleate, AJ-2615), a novel calcium antagonist, its metabolites and their enantiomers were studied in vitro. Monatepil maleate inhibited calcium-induced contractions of rat thoracic aorta (pA2 = 8.71) and l-phenylephrine-induced contractions of rabbit superior mesenteric artery (IC50 = 56.6 nmol/l). The calcium antagonistic activities of the metabolites of monatepil maleate (AJ-2615-sulfoxide A, AJ-2615-sulfoxide B and AJ-2615-sulfone) were 1/10 of that of monatepil maleate. However, their alpha 1-adrenergic receptor blocking activities were similar to or slightly more potent than that of monatepil maleate. The potencies of the calcium antagonistic activities of monatepil maleate and its enantiomers [(S)-AJ-2615 and (R)-AJ-2615] were in the order of (S)-AJ-2615 > monatepil maleate > (R)-AJ-2615 whereas no difference was observed among them in alpha 1-adrenergic receptor blocking activity. In calcium antagonistic and alpha 1-adrenergic receptor blocking activities, there was no difference between the enantiomers of monatepil maleate metabolites. In conclusion, there was a difference with several times in calcium antagonistic activity between the two enantiomers of monatepil maleate but not in their alpha 1-adrenergic receptor blocking activity.

Long-lasting antagonistic effects of monatepil on Ca2+ current in guinea-pig ventricular cells.

Monatepil maleate (CAS 103377-41-9, AJ-2615), a new derivative of dihydrodibenzothiepins, showed dose-dependent inhibition of Ca2+ current (ICa) in single cardiac cells isolated from guinea-pig ventricle. ICa was elicited by depolarization from -40 mV to +10 mV at 0.2 Hz. IC50 value of monatepil for the peak ICa at +10 mV was 18.7 nmol/l. The ICa inhibition was still sustained 30 min after washout, indicating that monatepil had long lasting activity in the mammalian single muscle cell.

Antihypertensive properties of a new long-acting angiotensin converting enzyme inhibitor in renin-dependent and independent hypertensive models.

The antihypertensive properties of a new long-acting, angiotensin-I-converting enzyme (ACE) inhibiting agent, (2S,3aS,7aS)-1-(N2-nicotinoyl-L-lysyl-gamma-D-glutamyl) octahydro-1H-indole-2-carboxylic acid (CAS 116662-73-8, DU-1777), were investigated orally in various experimental models of hypertension in comparison to a standard ACE inhibitor, lisinopril. The hypotensive potency of DU-1777 was not as marked as that of lisinopril in renin-dependent hypertensive models, i.e., two-kidney one-clip renal hypertensive rats (2K-1C RHR) (ED-20mmHg: 3.1 versus 1.0 mg/kg) or two-kidney two-clip renal hypertensive dogs (2K-2C RHD) (ED-20 mmHg: 2.5 versus 1.0 mg/kg), though the actions of the two drugs were both long-lasting and dose-related. When spontaneously hypertensive rats (SHR) were used, however, DU-1777 was as active as lisinopril (ED-20 mmHg: 17.9 versus 13.6 mg/kg). The most distinguishing results with DU-1777 were its hypotensive effects in renin-independent hypertensive models. In contrast to lisinopril, the drug produced a sustained and dose-related hypotensive effect in DOCA salt hypertensive rats (DOCA-HR) and one-kidney one-clip renal hypertensive rats (1K-1C RHR). There exists an inconsistency between the long duration of the agent's hypotensive action in all tested hypertensive models and its short duration of ACE inhibiting activity as demonstrated both in vivo and ex vivo. The sustained antihypertensive action of DU-1777 cannot be reasoned solely with respect to ACE inhibition, suggesting some additional mechanisms of action yet to be defined.