Up-regulation of protease-activated receptor-1 in diabetic glomerulosclerosis.

Patients with diabetes are under a hypercoagulable state leading to generation of thrombin. It is not known whether thrombin plays a role in the progression of diabetic nephropathy. We analyzed gene expression of two thrombin receptors, protease-activated receptor-1 (PAR-1) and PAR-4 in the kidney of diabetic db/db mice.

Collaborative work on evaluation of ovarian toxicity. 3) Effects of 2- or 4- week repeated-dose toxicity and fertility studies with tamoxifen in female rats.

To assess whether ovarian histopathological examination in repeated-dose rodent toxicity study could reliably anticipate toxic effects on female reproductive function and to assess whether ovarian change could be detected in a 2-week repeated-dose toxicity study, tamoxifen was administrated orally to female rats at 0.005, 0.03, or 0.

Effects of reduced food intake on toxicity study parameters in rats.

This study comprehensively describes the effects of various levels of food reduction on a wide range of toxicological parameters in dietary-optimized rats (fed with approximately 75% of ad libitum food consumption daily; 16 g and 22 g/day for females and males, respectively) that has been established as a nutritionally appropriate and well-controlled animal model in conducting toxicity studies. Toxicological parameters, including general condition, ophthalmology, clinical pathology and anatomic pathology, were examined in dietary-optimized Crl:CD(SD) female and male rats fed 16 g and 22 g/day (control), 12 g and 17 g/day (75% group), 8 g and 11 g/day (50% group), or 4 g and 6 g/day (25% group), respectively for 2 weeks. There was mortality and morbidity including reddish urine in 25% group females.

Use of whole sheep red blood cells in ELISA to assess immunosuppression in vivo.

An enzyme-linked immunosorbent assay (ELISA) using whole sheep red blood cells (SRBC) has been reported as one of the methods for detecting a T-lymphocyte-dependent antibody response. However, it has not been widely used because of SRBC problems such as the weak attachment to ELISA plates, specificity and short-term stability. The objectives of this study were to address these issues and to validate the SRBC-specific antibody response assay.

Beneficial effect of moderate food restriction in toxicity studies in rats.

Moderate food restriction (FR) has been established as a nutritionally appropriate and well-controlled method with long-term beneficial effects in conducting toxicity and carcinogenicity studies in rodents. This study describes the early effects of moderate FR on toxicity study parameters in rats and on the variability of these parameters. Physical signs, body weight, food and water consumption, and clinical pathology parameters were examined in a 4-week study in which rats were moderately food-restricted or fed ad libitum (AL).

A neuropeptide Y Y5 antagonist selectively ameliorates body weight gain and associated parameters in diet-induced obese mice.

Neuropeptide Y (NPY) is thought to have a major role in the physiological control of energy homeostasis. Among five NPY receptors described, the NPY Y5 receptor (Y5R) is a prime candidate to mediate some of the effects of NPY on energy homeostasis, although its role in physiologically relevant rodent obesity models remains poorly defined. We examined the effect of a potent and highly selective Y5R antagonist in rodent obesity and dietary models.

The functional shift of endothelin receptor subtypes in dogs with heart failure produced by rapid ventricular pacing.

To clarify the functional role of endothelin-A/endothelin- B (ETA/ETB) receptors in congestive heart failure (CHF), we examined the effects of a non-selective endothelin receptor agonist, endothelin-1 (ET-1), and a selective ETB receptor agonist, sarafotoxin S6c. CHF was induced in dogs by rapid ventricular pacing and resulted in decreased left ventricular dp/dtmax, decreased cardiac output and increased pulmonary vascular resistance. Sarafotoxin S6c (0.

Losartan ameliorates progression of glomerular structural changes in diabetic KKAy mice.

Pathological changes in glomerular structure are typically associated with the progression of diabetic nephropathy. The involvement of angiotensin II (AII) in pathogenesis of diabetic nephropathy has been extensively studied and the therapeutic advantages associated with blockade of renin-angiotensin system (RAS), primarily with angiotensin converting enzyme (ACE) inhibitors, has been well-documented. We studied the effect of RAS blockade with an AII receptor antagonist (losartan) vs.

Potent and orally active ET(A) selective antagonists with 5,7-diarylcyclopenteno[1,2-b]pyridine-6-carboxylic acid structures.

The synthesis and structure-activity relationships of a series of 5,7-diarylcyclopenteno[1,2-b]pyridine-6-carboxylic acids are described. Our efforts have been focused on modification of the aryl ring at the 5-position and the alkyl substituent at the 2-position of the bottom 4-methoxyphenyl ring in an effort to develop orally available ET(A) selective antagonists with safer profiles in terms of the P-450 enzyme inhibitory activity. Incorporation of a hydroxymethyl group as an alkyl substituent in methylenedioxyphenyl and 6-dihydrobenzofuran derivatives led to the identification of orally bioavailable ET(A) selective antagonists 1f and 7f.

[A new system using NMR technology for measurement of body composition in experimental animals].

Measurement of body composition (fat mass) is an important item in pathophysiological and pharmacological studies using small animals (mice) in the fields of obesity and diabetes. The existing methods are, however, difficult, time consuming, and require a shielding facility. Now a novel system using nuclear magnetic resonance (NMR) technique was developed for measurement of body composition in small animals (mice) that provides noninvasive and rapid measurement without anesthetics; we introduced and evaluated this system and tried another application of this system.

Structure-activity relationships of a novel class of endothelin receptor selective antagonists; 6-carboxy-2-isopropylamino-5,7-diarylcyclopenteno[1,2-b]pyridines.

The synthesis and structure-activity relationships of 6-carboxy-2-isopropylamino-5,7-diarylcyclopenteno[1,2-b]pyridine class of ET(A) receptor selective antagonists were described. These derivatives were prepared from the optically active key intermediates (3, 4, 10, and 13). Optimization of the substituent at the 2-position of the bottom 4-methoxyphenyl ring of the lead compound 1 led to identification of 2-hydroxy-1-methylethoxy (2g and h), hydroxyalkyl (2i, m, and p), 3-methoxy-2-methylpropyl (2t and u), N-acetyl-N-methylaminomethyl (2v), and 2-(dimethylcarbamoyl)propyl (2w) derivatives that showed greater than 1000-fold selectivity for the ET(A) receptor over the ET(B) receptor with excellent binding affinity (IC(50)<0.

Effects of muscarinic receptor antagonists with or without M2 antagonist activity on cholinergic reflex bronchoconstriction in ovalbumin-sensitized and -challenged mice.

To investigate whether the inhibition of muscarinic M(2) receptors results in the enhancement of reflex bronchoconstriction under airway hyperresponsiveness, we evaluated the effects of muscarinic antagonists with or without M(2) antagonist activity on methacholine (MCh)- and SO(2)-induced airway responses in ovalbumin (OVA)-sensitized and -challenged mice. In this model, similar airway hyperresponsiveness to MCh (12 mg/ml) was observed on Days 31 and 37 (2.2-fold and 2.

Late-onset obesity in mice transgenic for the human renin gene.

We previously generated a strain of transgenic mice carrying the human renin gene, hRN8-12, in the background of C57BL/6j. In this study, we discovered that hRN8-12 male mice, but not females, developed obesity starting at 15 weeks of age. The body weight of 60-week-old male transgenic mice was 2 times higher than that of age-matched wild-type mice.

[Pharmacological profile and clinical effects of montelukast sodium (Singulair chewable tablet), an antiasthmatic agent].

Montelukast (Singulair) is an antiasthmatic agent that has the chemical structure of a quinoline. Montelukast has a high affinity for the CysLT1 receptor and a potency that is not influenced by human serum protein. Montelukast antagonizes contractions of guinea-pig trachea induced by LTD4 in a competitive manner.

Structure-Activity relationships of 2-substituted 5,7-Diarylcyclopenteno[1,2-b]pyridine-6-carboxylic acids as a novel class of endothelin receptor antagonists.

Synthesis and structure-activity relationships of 2-substituted-5,7-diarylcyclopenteno[1,2-b]pyridine-6-carboxylic acids, a novel class of endothelin receptor antagonists, were described. Derivatization of a lead structure 1 (IC(50)=2.4nM, 170-fold selectivity) by incorporating a substituent such as an alkyl, alkoxy, alkylthio, or alkylamino group into the 2-position of the cyclopenteno[1,2-b]pyridine skeleton was achieved via the key intermediate 8.

The subtypes of muscarinic receptors for neurogenic bladder contraction in rats.

We evaluated in vivo functional selectivity profiles for muscarinic M(2) and M(3) subtypes of four muscarinic antagonists: Compound A (a novel muscarinic receptor antagonist with M(2)-sparing antagonistic activity), darifenacin, (a muscarinic M(3) receptor antagonist); methoctramine (a muscarinic M(2) receptor antagonist) and tolterodine (a nonselective muscarinic receptor antagonist), and compared the inhibition potency on distention-induced bladder contraction in rats. In an in vivo functional study, Compound A (0.03-10 mg/kg, i.

BQ-788, a selective endothelin ET(B) receptor antagonist.

We describe characteristics of a selective endothelin (ET) ET(B) receptor antagonist, BQ-788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D-1-methoxycarbonyltryptophanyl-D-norleucine], which is widely used to demonstrate the role of endogenous or exogenous ETs in vitro and in vivo. In vitro, BQ-788 potently and competitively inhibited (125)I-labeled ET-1 binding to ET(B) receptors in human Girrardi heart cells (hGH) with an IC(50) of 1.2 nM, but only poorly inhibited the binding to ET A receptors in human neuroblastoma cell line SK-N-MC cells (IC(50), 1300 nM).

6-Carboxy-5,7-diarylcyclopenteno[1,2-b]pyridine derivatives: a novel class of endothelin receptor antagonists.

Compounds (2-5) with a 6-carboxy-5,7-diarylcyclopentenopyridine skeleton were designed, synthesized, and identified as a new class of potent non-peptide endothelin receptor antagonists. The regio-isomer 2 was found to show potent inhibitory activity with an IC(50) value of 2.4 nM against (125)I-labeled ET-1 binding to human ET(A) receptors and a 170-fold selectivity for ET(A) over ET(B) receptors.