Inhibition of serum angiotensin-converting enzyme in rabbits after intravenous administration of enalaprilat-loaded intact erythrocytes.

Encapsulation of drugs in intact erythrocytes, because of the profound characteristics of these natural microspheres, has gained considerable attention in recent years. In this study, the inhibition time courses of serum angiotensin-converting enzyme (ACE) activity after intravenous administration of enalaprilat encapsulated in intact erythrocytes was evaluated and compared with free drug, in a rabbit model. Three groups of animals each received free drug, drug-loaded erythrocytes or sham-encapsulated erythrocytes.

The role of the interaction between endogenous opioids and nitric oxide in the pathophysiology of ethanol-induced gastric damage in cholestatic rats.

Interaction between endogenous opioids and nitric oxide (NO) has been shown in different biological models and pharmacological evidence suggest that opioids can induce NO release in endothelium as well as in neural cells. Cholestasis is associated with NO overproduction. The reason for increased NO synthesis is not clearly known but it can potentiate development of gastric mucosal damage in cholestatic subjects.

Mesenteric vascular bed responsiveness in bile duct-ligated rats: roles of opioid and nitric oxide systems.

Changes in vascular responsiveness are proposed as the basis for some of the cardiovascular complications in cholestasis. Cholestasis is also associated with accumulation of endogenous opioid peptides and evidence of overproduction of nitric oxide (NO). The possible role of NO or opioid system in cholestasis-induced mesenteric vascular bed responsiveness was investigated.

Role of nitric oxide in hypodipsia of rats with obstructive cholestasis.

Cholestasis is associated with the overproduction of nitric oxide (NO), and NO acts as an inhibitory mechanism when thirst is stimulated by water deprivation or by angiotensin II. Due to the presence of hypodipsia in the cholestatic condition, we have compared the rate of water intake between bile duct-ligated (cholestatic) and sham-operated rats. We have evaluated the effect of NO synthesis inhibition by N(G)-nitro-L-arginine (L-NNA, 10 mg kg(-1)/day) on the rate of water intake in cholestatic rats.

The role of nitric oxide in bradycardia of rats with obstructive cholestasis.

Nitric oxide (NO) has an important role in controlling heart rate and contributes to the cholinergic antagonism of the positive chronotropic response to adrenergic stimulation. Based on evidence of NO overproduction in cholestasis and also on the existence of bradycardia in cholestatic subjects, this study aimed to evaluate the chronotropic effect of epinephrine in isolated atria of cholestatic rats and determine whether alterations in epinephrine-induced chronotropic responses of cholestatic rats are corrected after systemic inhibition of NO synthase (NOS) with N(G)-nitro-L-arginine (L-NNA). Male Sprague-Dawley rats were used.

L-arginine/nitric oxide pathway and interaction with lead acetate on rat submandibular gland function.

The effects of lead acetate, L-arginine (nitric oxide precursor) and L-NAME (nitric oxide synthesis inhibitor) on rat submandibular secretory function were studied. Pure submandibular saliva was collected intraorally from anaesthetized rats by a micro polyethylene cannula using pilocarpine as secretagogue. Treatment for twenty-eight days with three doses of lead acetate (0.

Alteration by cadmium of rat submandibular gland secretory function and the role of the l-arginine/nitric oxide pathway.

The effects of cadmium, l-arginine (nitric oxide precursor) and N(omega)-nitro-l-arginine methyl ester (l -NAME) as a nitric oxide synthesis inhibitor and cotreatment of them on rat submandibular secretory function were studied. Pure submandibular saliva was collected intraorally by micro polyethylene cannula from anaesthetized rats using pilocarpine as secretagogue. Fourteen days treatment with 10 mg l(-1)cadmium as cadmium chloride in drinking water caused significant alterations on salivary function.

Subsensitivity to opioids is receptor-specific in isolated guinea pig ileum and mouse vas deferens after obstructive cholestasis.

The rate and degree of subsensitivity development to morphine (mu-opioid receptor, preferred, but not selective agonist) and U50488H (highly selective kappa-opioid receptor agonist) were assessed in vitro on guinea pig ileum (GPI) of cholestatic animals 2, 5, and 7 days after bile duct ligation. In addition to this phenomenon of morphine, the effects of U50488H and SNC 80 (highly selective delta-opioid receptor agonist) were studied in vitro on mice vas deferens (MVD) of cholestatic animals 2, 5, 7, 10, and 15 days after bile duct ligation. The IC(50) for each compound was determined in these preparations.

Effect of chronic lithium administration on endothelium-dependent relaxation in rat aorta.

1. The effects of chronic lithium administration on the relaxant responses of rat thoracic aortic rings in the presence of indomethacin (a cyclo-oxygenase inhibitor) and/or NG-nitro-L-arginine (L-NOARG; a nitric oxide synthase inhibitor) to acetylcholine (ACh) or sodium nitroprusside were investigated in the present study. 2.

The effect of thyroid hormone on orthodontic tooth movement in rats.

The major goals of this study were to determine the effects of different doses of thyroxin on the rate of orthodontic tooth movement and the force-induced root resorption. In this study fifty male Sprague--Dawley rats were divided into five groups: a normal group with no intervention; a control group in which appliances were placed and 10 ml/kg i.p.

Plasma membrane calcium ATPase isoforms in astrocytes.

The plasma membrane Ca(2+)-ATPase (PMCA) is an essential component of the machinery responsible for cellular Ca(2+) homeostasis. Together with the Na(+)/Ca(2+) exchanger, the plasma membrane Ca(2+)-ATPase (PMCA) is responsible for the extrusion of Ca(2+) from the cytosol. Although both PMCAs and Na(+)/Ca(2+) exchangers are present in high amounts in the brain, it is thought that only the latter localize to glia.

Increase by NO synthase inhibitor of lead-induced release of N-acetyl-beta-D-glucosaminidase from perfused rat kidney.

Urinary N-acetyl-beta-D-glucosaminidase (NAG) had been shown to be a useful early marker of renal injury such as lead nephrotoxicity. This study investigated the effect of lead acetate on nephrotoxicity and its correlation with the nitric oxide (NO) system by determining the NAG release in perfused rat kidney. Lead acetate caused a time and concentration-dependent increase in enzymuria.

A comparison of ketorolac tromethamine and acetaminophen codeine in the management of acute apical periodontitis.

Effective management of severe endodontic pain is often a major problem. The analgesic effect of ketorolac tromethamine (Toradol, 10 mg p.o.

N(G)-nitro-L-arginine methylester is protective against ethanol-induced gastric damage in cholestatic rats.

In this study the effect of nitric oxide (NO) synthesis inhibition on ethanol-induced gastric damage was evaluated in bile duct-ligated, sham-operated and unoperated rats. The animals were injected intraperitoneally with saline, L-arginine (200 mg/kg) or N(G)-nitro-L-arginine methylester (L-NAME) in doses of 5, 15 and 30 mg/kg, 30 min before ethanol administration. The animals were killed 1 h after ethanol administration and their stomachs were removed for measurement of gastric mucosal damage.

Naloxone is protective against indomethacin-induced gastric damage in cholestatic rats.

We compared indomethacin-induced gastric damage in three groups of rats-bile duct-ligated, sham-operated, and unoperated-and evaluated the role of the opioid system by blocking the effects of endogenous opioids with naloxone. Indomethacin was administered orally in a dose-dependent manner at 10, 30, and 45 mg/ kg. Naloxone was administered intraperitoneally in several doses of 0.

Synthesis and pharmacological activity of thebaine-derived mu-opioid receptor agonists.

Thebaine-derived mu-opioid agonists were synthesized through the reaction of thebaine with N-aryl maleimide and tested for opioid activity. Morphine was used as reference compound. Our results show that an attachment of aryl succinimide group to thebaine produced series of compounds with mu-opioid agonist activity.

Effects of chronic lithium on ototoxicity induced by gentamicin and amikacin in guinea-pigs.

The effects of chronic lithium co-therapy on the expression of gentamicin and amikacin ototoxicity were tested in guinea-pigs. Intramuscular injection of different doses of gentamicin (5, 10 mg/kg/day) and amikacin (150, 300 mg/kg/day) for three weeks, induced hearing loss consistent with the established pattern of aminoglycoside ototoxicity. Lithium salts remains one of the most widely used treatment for depressive illness.

Endogenous nitric oxide modulates naloxone-precipitated withdrawal signs in a mouse model with acute cholestasis.

Cholestasis liver disease is associated with clinical and experimental findings consistent with increased opioidergic neuromodulation, increased plasma total activity, and elevated plasma enkephalin concentrations. The effect of the nitric oxide (NO) synthase inhibitor, L-nitro-arginine (L-NA, 0.03, 0.

The lithium ratio and the incidence of side effects.

1. During a prospective and outpatient study the correlation between the lithium ratio and the incidence of lithium side effects and type of comedications was studied in 51 Iranian bipolar patients by using new direct method of measuring erythrocyte lithium concentration. 2.

Enhancement of aspirin-induced gastric damage by cholestasis in rats.

In this study the severity of aspirin-induced gastric mucosal damage was investigated in rats with obstructive cholestasis. Cholestasis was induced by ligation and resection of the bile duct under general anesthesia. Two weeks after operation, the rats were fasted for 24 hours.

Calcium release by diltiazem from isolated sarcoplasmic reticulum of rabbit skeletal muscle.

1. The effect of diltiazem on isolated sarcoplasmic reticulum (SR) from rabbit skeletal muscle was studied. To observe calcium movement into and out of the SR, a fluorescent chelate probe technique with chlortetracycline (CTC) as a reagent was employed.

Syntheses and calcium channel antagonist activity of nifedipine analogues with methylsulfonylimidazolyl substituent.

Various diester analogues of nifedipine in which the ortho nitrophenyl group at position 4 is replaced by 1-methyl-2-methylsulfonyl-5-imidazolyl substituent, were synthesized and evaluated as calcium channel antagonists on guinea-pig ileal smooth muscle. Nifedipine was used as a standard. Compound 6n was found to be the most active.

Decrease in erythrocyte:plasma lithium ratio by concurrent administration of psychotropic drugs and lithium in mice.

1. Previous studies paying attention to concurrent use of lithium (Li+) with a neuroleptic were not done under constant and controlled conditions. We were therefore encouraged to do a prospectively controlled study, presuming constant relevant factors, on concomitant use of Li+ with neuroleptic as well as other psychotropic agents.

The effect of acute lithium and rubidium pretreatment on apomorphine-induced pecking in pigeons.

The effects of different doses of lithium (5-320 mg/kg intramuscularly) and rubidium (0.25 32 mg/kg intramuscularly) on apomorphine-induced pecking were investigated in pigeons. These two cations did not induce pecking by itself.

Alterations of physostigmine-induced yawning by chronic lithium administration in rats.

The effect of chronic lithium pretreatment on physostigmine-induced yawning was investigated in male rats. Intraperitoneal administration of physostigmine to rats induced yawning in a biphasic manner. However the maximum response was obtained by 0.