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Biomedical subjects

S S Parmar

Publications and source records attributed to S S Parmar.

At least 55 records · Page 3Linked to original sources
PubMed1983

Role of monoamine oxidase-B in medroxyprogesterone acetate (17-acetoxy-6 alpha-methyl-4-pregnene-3, 20-dione) induced changes in brain dopamine levels of rats.

The effect of medroxyprogesterone acetate (MPA) on brain monoamine levels and monoamine oxidase (MAO) activity was studied in adult, healthy, non-pregnant female rats. MpA was injected in a single dose of 100 mg/kg i.m. Dopamine (DA), noradrenaline (NA), 5-hydroxytryptamine (5-HT) levels and MAO activity were estimated fluorometrically in rat brian. No change in DA, NA, 5-HT or MAO activity was observed after 7 days of MPA treatment while a significant decrease in DA levels along with a significant increase in MAO activity was observed after 21 days of MPA treatment. However, there was no change in NA and 5-HT levels after 21 days of MPA administration. The selective reduction of DA by MPA could be due to an increase in MAO-B activity. MPA does not appear to increase MAO-A activity because neither of the specific substrates (NA and 5-HT) of MAO-A was found to be decreased inspite of the increase in MAO activity as estimated by the kynuramine method. These findings suggest the importance of MAO-B also in DA metabolism in rat brain.

Animals↗
PubMed1983

Effects of helium-oxygen and hyperbaric helium-oxygen environment on drug-metabolizing enzyme activity in rat liver.

The effects of room-air normoxic (22 degrees C +/- 1 degree C), 1.2-ATA He-O2 (400 mmHg PO2, 29.0 degree C +/- 1 degree C), and 21-ATA He-O2 (400 mmHg PO2, 32.5 degrees C +/- 1 degree C) environments were investigated on the activity of drug-metabolizing enzyme systems in rat liver, as monitored by O-dealkylation and N-dealkylation reactions. Continuous exposure of rats to both He-O2 environments for 12 days significantly increased the in vitro activity of drug-metabolizing enzymes in liver preparations. The increase in the in vitro O-dealkylation of p-nitroanisole based on product formed X mg protein-1 X 20 min-1 was 32.2% (P less than 0.05) between normoxic animals and those exposed to 1.2 ATA He-O2, and 24.4% (P less than 0.01) in animals exposed to between 1.2 and 21 ATA He-O2. A significant increase of 48.8% (P less than 0.001) was noted between normoxic animals and those exposed to 21 ATA He-O2. Similar differences were noted if the data were expressed on the basis of 200 mg liver wet wt. The N-dealkylation of morphine based on product formed X mg protein-1 X 20 min-1 was significantly increased between animals kept at normoxic and at 1.2-ATA He-O2 conditions (17.6%, P less than 0.05) and between animals kept at normoxic and at 21 ATA He-O2 conditions (28.2%, P less than 0.05). No significant differences for N-dealkylation of morphine were noted between animal groups at 1.2 and those at 21 ATA He-O2 nor between any animal groups for N-dealkylation of cocaine.

Animals↗
PubMed1982

Digoxin-quinidine interaction in unanesthetized guinea pigs.

The clinically relevant interaction between quinidine (3 mg/kg) and digoxin (0.6 mg/kg plus 20 microCi 3H-digoxin) was investigated using unanesthetized and unrestrained guinea pigs for in vivo pharmacokinetic and tissue disposition studies. Quinidine caused a significant elevation of plasma levels of digoxin as early as 5 min after injection, and the increase persisted for at least 8 h. A significant decrease in the volume of distribution for digoxin from 3.6 to 2.7 liters/kg (20%) was observed in quinidine-treated animals. No change was noted in the dominant elimination half-life of digoxin in quinidine-treated animals. The decreased volume of distribution appeared to be due to displacement of digoxin from tissue stores by quinidine as evidenced by decreased tissue to plasma ratios for kidney (41%), intestine (41%), fat (33%), lung (31%), left ventricle (27%), liver (24%), left atrium (22%), right ventricle (21%), right atrium (18%), pancreas (12%), and bladder (-4%) samples.

Animals↗
PubMed1982

Antiinflammatory and antiproteolytic properties of substituted tetrazolycarbamides.

Eight 1-(5-aryl-2-acetyltetrazolyl)-3-substituted carbamides were evaluated for their antiinflammatory and antiproteolytic properties. The protection afforded by these compounds (100 mg/Kg, i.p.) against carrageenin-induced edema in rats ranged from 10-45%. Oxyphenbutazone (40 mg/kg, i.p.) and hydrocortisone (10 mg/kg, i.p.), used as reference drugs, possessed 53% and 45% antiinflammatory activity, respectively. All substituted tetrazolyl carbamides (1 mM) possessed antiproteolytic activity which was reflected by their ability to inhibit the activity of trypsin during hydrolysis of bovine serum albumin. The degree of protection observed against trypsin-induced hydrolysis ranged from 25-62% while such an inhibition with sodium salicylate (1 mM) was 52%.

Animals↗
PubMed1982

Anticonvulsant activity and monoamine oxidase inhibitory properties of substituted 1,2,4-triazoles.

Nine 5-(3,4,5-trimethoxyphenyl)-4-substituted aryl-3-hydrazinocarbonylmethylthio-4H-1,2,4-triazoles were investigated for their anticonvulsant and monoamine oxidase inhibitory properties. The protection afforded by these compounds at a dose of 100 mg/kg ranged from 20-90% against pentylenetetrazol-induced seizures and 20-40% against electric shock-induced convulsions. The degree of in vitro monoamine oxidase inhibition by substituted triazoles ranged from 41-80%, 18-36% and 20-40% using kynuramine, tyramine and 5-hydroxytryptamine as substrate, respectively. The approximate LD50 values of greater than 1000 mg/kg exhibited low toxicity of substituted triazoles.

Animals↗
PubMed1981

Anti-inflammatory, antiproteolytic, and antihemolytic properties of pyrrole carboxylic acids.

Eight substituted pyrrole carboxylic acids were evaluated for their anti-inflammatory activity against carageenin-induced edema in rats. The protection afforded by seven of these compounds at a dose of 100 mg/kg i.p. ranged from 11 to 42%. Indomethacin (10 mg/kg i.p.), used as a reference drug, possessed 45% anti-inflammatory activity under similar experimental conditions. The ability of these compounds to exhibit in vitro antiproteolytic activity was reflected by their ability to inhibit trypsin-induced hydrolysis of bovine serum albumin. The inhibition of the activity of trypsin by these substituted pyrrole carboxylic acids (1 mM) ranged from 42 to 90% while such an inhibition with indomethacin (1 mM) was 95%. The in vitro membrane stabilizing property of these substituted pyrrole carboxylic acids was observed by their ability to provide protection against heat-induced dog erythrocyte hemolysis. The I50 value of these compounds, representing the concentration required to inhibit one-half of heat-induced erythrocyte hemolysis, ranged from 0.29 to 6.0 mM. Such an inhibition was concentration-dependent and biphasic in nature. The I50 value for indomethacin, showing greater antihemolytic activity was found to be 0.02 mM under similar experimental conditions. These results have provided some correlation of anti-inflammatory activity with antiproteolytic and membrane stabilizing properties for substituted pyrrole-3-carboxylic acids alone but not for pyrrole-2-carboxylic acids.

Animals↗
PubMed1980

Correlation between monoamine oxidase inhibitors and anticonvulsants.

Monoamine oxidase inhibitory and anticonvulsant properties of 2-substituted styryl-6-bromo-3-(4-ethylbenzoate/4 benzhydrazide)-4-quinazoles are studied. All styryl quinazolone esters except compound number 9 exhibited monoamine oxidase inhibitory properties during oxidative deamination of kynuramine. Corresponding hydrazides were found to have relatively higher activity. All these quinazolones were able to protect against pentylenetetrazol induced seizures. These observations in general do not prove that monoamine oxidase inhibitory properties represent the biochemical basis for the anticonvulsant activity of these compounds.

Animals↗
PubMed1979

13C-NMR spectra of strychnos alkaloids: brucine and strychnine.

The natural abundance 13C-NMR spectra of brucine and strychnine were obtained using the pulse Fourier transform technique. The chemical shifts of various carbon resonances were assigned on the basis of substituent effects on benzene shifts, intesities of signals, multiplicites generated in single-frequency off-resonance-decoupled spectra, and comparisons with the chemical shifts of structurally related compounds.

Chemical Phenomena↗
PubMed1979

Fourier transform carbon-13 NMR spectra of ampyrone and aminopyrine.

The natural abundance 13C-NMR spectra of ampyrone and aminopyrine were obtained using the pulse Fourier transform technique. The chemical shifts were assigned with the help of the chemical shift theory, multiplicity generated in single-frequency off-resonance decoupled spectra, relaxation time, and comparison with structurally related compounds.

Aminopyrine↗
PubMed1979

13C-NMR spectra of alpha-adrenergic blocking agents.

The natural abundance 13C-NMR spectra of five alpha-adrenergic blocking agents, tolazoline, dibenamine, azapetine, phenoxybenzamine, and phentolamine, are reported. The chemical shifts of various carbon resonances were assigned on the basis of chemical shift theory, multiplicities observed in single-frequency off-resonance-decoupled spectra, relaxation times, and comparisons with the chemical shifts of model compounds.

Adrenergic alpha-Antagonists↗
PubMed1979

Anticonvulsant, analgesic and monoamine oxidase inhibitory properties of newer 4-hydroxy-4-phenylpiperidinocarbamides.

Fourteen 1-[N-acetyl(4-hydroxy-4-phenyl-piperidino)]-3-aryl carbamides were synthesized, characterized and evaluated for their anticonvulsant, analgesic and monoamine oxidase inhibitory properties. All carbamides (100 mg/kg, i.p.) provided 20--60% protection against pentylenetetrazol-induced seizures in mice. The analgesic activity possessed by these carbamides, with the exception of two compounds, was reflected by their ability to provide 17--67% protection against tail pinch response in mice. All carbamides (1 mM) inhibited (5--90%) in vitro activity of rat brain monoamine oxidase. The low toxicity of these carbamides was reflected by their higher approximate LD50 values which ranged from 500 - greater than 1000 mg/kg.

Analgesics↗
PubMed1978

Anticonvulsant and antiproteolytic properties of 2,5-disubstituted oxadiazoles and their inhibition of respiration in rat brain homogenates.

Eight 2-(3,4-methylenedioxyphenyl)-5-arylamino1,3,4-oxadiazoles were synthesized, characterized by their sharp melting points, elemental analyses, and IR spectra, and evaluated for anticonvulsant activity. The protection afforded by oxadiazoles (100 mg/kg ip) against pentylenetetrazol (90 mg/kg sc)-induced convulsions ranged from 50 to 80%. All oxadiazoles inhibited the respiratory activity of rat brain homogenates during oxidation of pyruvate, alpha-ketoglutarate, and succinate. The presence of added nicotinamide adenine dinucleotide (NAD) to the reaction mixture during oxidation of pyruvate decreased the degree of inhibition. All oxadiazoles possessed antiproteolytic activity that was reflected by their ability to decrease trypsin-induced hydrolysis of bovine serum albumin. Such an inhibition was concentration dependent and ranged from 10.2 to 47.5 and from 15.7 to 71.8% by 0.5 and 1 mM oxadiazoles, respectively. All oxadiazoles competitively inhibited in vitro succinate dehydrogenase activity of rat brain homogenates.

Animals↗