2024-03-29T04:23:42+04:30 http://ijpt.iums.ac.ir/browse.php?mag_id=3&slc_lang=en&sid=1
3-22 2024-03-29 10.1002
Iranian Journal of Pharmacology and Therapeutics 3 9 10 7 2003 2 1 G-protein Coupled Receptor Dimerization Nikzad Nikbin Christine Edwards Christopher A Reynolds A growing body of evidence suggests that GPCRs exist and function as dimers or higher oligomers. The evidence for GPCR dimerization comes from biochemical, biophysical and functional studies. In addition, researchers have shown the occurrence of heterodimerization between different members of the GPCR family. Two receptors can interact with each other to make a dimer through their extracellular loops, transmembrane helices and intracellular loops. The nature of bonds between two receptors can vary from covalent (e.g. disulphide bonds) to non-covalent (for instance hydrophobic interactions between trans-membrane helices or coiled coil structures) or a combination of both. Dimerization can occur in and affect different stages of a receptors life, namely trafficking, signaling and internalization, and can be seen as the natural way to regulate receptor activity or increase the functional repertoire of proteins. Different structures for GPCR dimers have been proposed, for example a simple contact dimer or an interlocking domain-swapped structure. Here we introduce some of the information available on GPCR dimerization, which includes early studies that had been dismissed until the relatively recent past and some of the more recent data which has vindicated these early studies. 2003 5 01 1 0 http://ijpt.iums.ac.ir/article-1-22-en.pdf
3-21 2024-03-29 10.1002
Iranian Journal of Pharmacology and Therapeutics 3 9 10 7 2003 2 1 An Improved Method for Injection of Bolus Doses of Drugs into the Perfusion Circuit of Isolated Perfused Rat Kidney Utilizing a Six-port Injection Valve Soltan Ahmed Ebrahimi Ali Rouzrokh The isolated perfused rat kidney experiment was introduced in 1959 for studying the regulation of renal blood flow and is recognized as a valuable preparation for studying physiological and biochemical aspects of renal function such as hemodynamics, glomerular filtration rate (GFR) and overall handling of fluids. Dose-response curves are obtained by injection of bolus doses of drugs into the perfusion line. However current injection methods can cause several problems such as low reproducibility and altered baseline pressure. The aim of the present work is to develop a simple method of introducing the drug into the perfusion circuit which is free from these aberrations. This was achieved using a six-way injection valve placed in the perfusion circuit, just before the kidney. To assess the reproducibility of this method, 400 L epinephrine (10-7 M) was injected seven times into an isolated perfused rat kidney. The mean peak pressure rise (mmHg) was 30.30.6, 28.50.8 and 27.10.6 at 100, 120 and 140 mmHg base perfusion pressures respectively. Base pressure returned to pre-injection levels under all conditions tested. Low standard deviation of pressure maxima indicates the high reproducibility of this method while multiple injections can be made in a relatively shorter time. This method can be applied to all organ perfusion setups such as isolated hind limb, tail, arteries and arterioles. 2003 5 01 12 0 http://ijpt.iums.ac.ir/article-1-21-en.pdf
3-20 2024-03-29 10.1002
Iranian Journal of Pharmacology and Therapeutics 3 9 10 7 2003 2 1 Stereospecific Determination of Mefloquine in Whole Blood by HPLC Effat Souri Hassan Farsam Ali Zare Mefloquine, as a racemic mixture, is used for the treatment and prophylaxis of malaria. Stereoselective pharmacodynamic and pharmacokinetic differences has been observed for mefloquine. In this study a modified stereoselective HPLC method is presented for determination of mefloquine (MFQ) enantiomers in whole blood. The assay involved liquid-liquid extraction of MFQ from biological fluids with methyl tert-butyl ether in the presence of sodium hydroxide and derivatization of the residue by (+)-1-(9-fluorenyl) ethyl chloroformate (FLEC) as chiral derivatizing reagent. Separation of the resulting diastereomers was performed on a Novapack C18 reversed-phase cartridge column using acetonitrile, water, glacial acetic acid (730:270:0.7, v/v/v) as the mobile phase with a flow-rate of 1 mL/min. Using 500 L of whole blood, the limit of determination was 50 ng/mL with fluorescence detection with excitation at 263 nm and emission at 475 nm for both enantiomers. This method is comparatively simple and practical for the determination of small amounts of mefloquine enantiomers. 2003 5 01 15 0 http://ijpt.iums.ac.ir/article-1-20-en.pdf
3-18 2024-03-29 10.1002
Iranian Journal of Pharmacology and Therapeutics 3 9 10 7 2003 2 1 A High-Performance Liquid Chromatographic Assay for the Determination of Losartan in Plasma Hassan Jalalizadeh Effat Souri Hassan Farsam Mehdi Ansari A rapid and sensitive HPLC method was developed for determination of losartan in plasma. Losartan was extracted from plasma by a two-step extraction procedure using chloroform as extracting solvent in acidic medium. HPLC analysis was performed on a cyano reversed-phase column using phosphate buffer (pH 4.3), acetonitrile (750:250, v/v) as mobile phase with a flow rate of 0.9 mL/min. Sodium diclofenac was selected as internal standard. Excellent linearity between the peak area ratios and losartan concentrations over the range of 2-200 ng/mL of plasma was observed. The limit of determination with UV detection at 225 nm, with a CV < 5% was 2 ng/mL in 500 L of plasma sample. The assay was rapid, safe and reliable for use in pharmacokinetic studies of losartan in human being. 2003 5 01 18 0 http://ijpt.iums.ac.ir/article-1-18-en.pdf
3-19 2024-03-29 10.1002
Iranian Journal of Pharmacology and Therapeutics 3 9 10 7 2003 2 1 Evaluation of Antibacterial Activity of Tribulus terrestris L. Growing in Iran Saied Kianbakht Fereshteh Jahaniani Tribulus terrestris is used as a urinary anti-infective in folk medicine. To validate this use, the in vitro antibacterial activity of methanolic extracts of different parts (fruits, stems plus leaves and roots) of T. terrestris L. growing in Iran was evaluated against four reference bacteria by broth dilution assay and agar diffusion assay. The MIC value of the methanolic extracts of fruits and stems plus leaves against all bacteria was 2 mg/mL and the MIC value of roots against S. aureus, E. faecalis and E. coli was 4 mg/mL and the MIC value of roots against P. aeruginosa was 2 mg/mL. In agar diffusion assay, the methanolic extracts of all parts of the plant showed considerable activity against all bacteria. 2003 5 01 22 0 http://ijpt.iums.ac.ir/article-1-19-en.pdf