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At least 19 recordsLinked to original sources

PubMed1985

Effects of isoxuprine and nylidrin on adrenoreceptors in rat vas deferens.

The interaction of isoxuprine and nylidrin with alpha 1- and beta 2-adrenoreceptors in rat vas deferens was examined using radioligand binding assays and physiological studies in vitro. Isoxuprine and nylidrin have a greater affinity for binding to alpha 1 (isoxuprine KD = 59 +/- 15 nM; nylidrin KD = 41 +/- 3 nM) than beta 2-(isoxuprine KD = 3,900 +/- 500 nM; nylidrin KD = 900 +/- 50 nM) adrenoreceptors in rat vas deferens. Vas deferens from rats pretreated for 16-24 h with reserpine (3 mg/kg i.p.) were exposed to 10 microM phenoxybenzamine for 15 min to inactivate alpha-adrenoreceptors. Under these conditions high concentrations of both isoxuprine and nylidrin relaxed vas deferens contracted with 55 mM K+, however the relaxation was not blocked by the beta-adrenoreceptor antagonist propranolol (10 microM). Both isoxuprine and nylidrin were potent competitive antagonists of alpha 1-adrenoreceptor mediated contraction of vas deferens. pA2 values for isoxuprine (6.9 +/- .05) and nylidrin (7.1 +/- .08) agreed well with KD values for binding to alpha 1-adrenoreceptors in vas deferens. The greater potency of isoxuprine and nylidrin in inhibiting alpha 1-adrenoreceptors than binding to beta 2-adrenoreceptors or causing nonspecific relaxation suggest that alpha-adrenoreceptor antagonist actions of these drugs may be important in their ability to inhibit smooth muscle tone.

Animals↗

PubMed1991

A randomized double-dummy comparison between indomethacin and nylidrin in threatened preterm labor.

We compared the tocolytic effect of indomethacin and nylidrin in a prospective double-blind trial in which the appearance of the tocolytic treatment (always intravenous infusion and rectal suppositories/oral capsules) was identical to the subjects. Sixty healthy women in imminent preterm labor between 25-34 weeks of singleton gestation were included. Thirty of these women received indomethacin (concomitantly with placebo infusion), with doses as follows: day 1, 100-mg rectal suppository followed by two oral capsules (50 mg) at 8-hour intervals; days 2 and 3, three 50-mg oral capsules each day. Thirty women received intravenous nylidrin (concomitantly with rectal/oral placebo), initiated with the dose of 50 micrograms/minute and continued at the dose of 100-150 micrograms/minute for a maximum of 3 days. Preterm labor was arrested for 24, 48, and 72 hours in 100, 96, and 90%, respectively, of subjects in the indomethacin group, compared with 100, 76, and 73% of women in the nylidrin group; the difference was significant (P less than .05) at 48 hours. Women progressed beyond 37 gestational weeks more commonly (P less than .05) with indomethacin (21 of 30, 70%) than with nylidrin (13 of 30, 43%). Indomethacin treatment was accompanied by maternal side effects 20% of the time, significantly less commonly (P less than .001) than with nylidrin (83%). The neonatal outcome was similar in the two study groups. We conclude from this double-dummy technique trial that indomethacin is more effective and better tolerated than nylidrin in arresting imminent preterm labor.

Adult↗

PubMed1979

Nylidrin: a potent anti-hypertensive agent in hypertensive rats.

Nylidrin HCl lowered the blood pressure and increased the heart rate of conscious, spontaneously hypertensive rats (SHR), Goldblatt hypertensive rats, and DOCA hypertensive rates. In SHR, the minimum effective dose was 0.5 mg/kg, s.c. At that dose, the anti-hypertensive activity of nylidrin lasted more than 3 hours. Propranolol reversed both effects on blood pressure and heart rate by nylidrin, whereas atenolol, a specific cardiac beta 1 blocker, only blocked or reversed the tachycardia caused by nylidrin but did not block the anti-hypertensive effect of the compound. In normotensive rats of Wistar/Kyoto strain (WKY) and Holtzman strain, nylidrin at 5 or 10 mg/kg, s.c., produced a transient hypotensive effect which lasted less than an hour and tachycardia that persisted for several hours. In WKY, atenolol prolonged the hypotensive activity of the compound by partially reversing the tachycardia. These observations indicate that SHR is more sensitive than WKY to the anti-hypertensive activity of nylidrin, which is probably caused by vasodilatation mediated by beta 2 receptors.

Animals↗

PubMed1997

Subtype-selective antagonism of NMDA receptors by nylidrin.

The 1,4-di-substituted piperidines ifenprodil, eliprodil, CP 101,606 ((1S,2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol ) and Ro 25-6981 ((R-(R*,S*))-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenyl-methyl)-1- piperidinepropanol) are allosteric antagonists of NMDA receptors. Inhibition of diheteromeric NMDA receptors by this class of antagonist is characterized by pronounced selectivity for NR1/2B subunit combinations. In the current study, we assayed effects of nylidrin, a structurally-related non-piperidine, on recombinant and neuronal NMDA receptors. Nylidrin was a potent (IC50 = 0.18 microM) antagonist of NR1A/2B receptors expressed in Xenopus oocytes and was at least 150-fold weaker against NR1A/2A and NR1A/2C receptors. The blockade of NR1A/2B responses by nylidrin was not surmounted by increasing the concentrations of glutamate or glycine and was not voltage-dependent. Potency of inhibition increased approximately 3-fold upon lowering extracellular pH from 8 to 6.8. Nylidrin inhibited NMDA responses in cultured rat cortical neurons with similar potency and apparent mechanism of action as the NR1A/2B receptors. Our results suggest that nylidrin interacts with the same allosteric inhibitory site previously described for the related piperidine antagonists, and should serve as a structural lead for designing novel subtype-selective inhibitors of NMDA receptors.

Animals↗

PubMed1985

Ocular hypotension in the rabbit. Receptor mechanisms of pirbuterol and nylidrin.

Pirbuterol and nylidrin, both purported sympathomimetic amines, reduced intraocular pressure (IOP) when given topically (50 microliter, 0.1%) to albino rabbits. Pirbuterol increased the cyclic-AMP concentration in aqueous humor by a factor of 3.25, while nylidrin had no effect on aqueous cyclic-AMP nor on adenylate cyclase activity of iris-ciliary body membranes assayed in vitro. Studies of the receptor affinity of pirbuterol, timolol and nylidrin were carried out on iris-ciliary body membranes by competition binding with radioactive ligands. Four ligands were used that appear to label separate subpopulations of adrenergic receptors; dihydroalprenolol (beta-receptors), WB-4101 (alpha 1-receptors) prazosin (alpha 1-receptor subpopulation) and yohimbine (alpha 2-receptors). Pirbuterol and timolol showed exclusive selectivity for beta-receptors with high affinities (Kd 12.6 and 0.48 nM, respectively) compared with other adrenergic receptor populations in iris-ciliary body. Nylidrin had high affinities for beta-receptors (Kd 22 nM) and for the subpopulation of alpha 1-receptors labelled by prazosin (Kd 6.5 nM), but showed 100-fold lower affinity and complex binding characteristics to the two other classes of alpha-adrenergic receptor sites labelled by WB-4101 and yohimbine, respectively. The results show that pirbuterol and timolol are highly beta-receptor selective and that hypotensive responses to these drugs are not mediated by the other classes of alpha-adrenergic receptor determined in this study. However, the hypotensive response to nylidrin may be related to its prazosin-like (alpha 1-receptor) antagonist properties with additional activity at beta-receptors.

Adenylyl Cyclases↗

PubMed1983

Antiallergic activity of nylidrin hydrochloride (RHC 3432-A). I. Effect on release of histamine in vitro from rat peritoneal mast cells, guinea pig lung slices and human basophils.

Nylidrin (RHC 3432-A) has been investigated for its antiallergic activity in three in vitro models. Nylidrin was an effective inhibitor of IgE-mediated release of histamine from passively sensitized rat peritoneal mast cells and human basophils, and of IgG1-mediated release of histamine from passively sensitized guinea pig lung slices. The inhibition of the release of histamine by nylidrin in all three models was not antagonized by propranolol, indicating that nylidrin does not inhibit histamine release via stimulation of beta-adrenergic receptors. Isoproterenol and epinephrine were effective as inhibitors of the release of histamine only from guinea pig lung while salbutamol and terbutaline had no effect on immunologic release of histamine in all three models. Detailed comparative studies with disodium cromoglycate (DSCG) indicated that the mechanism of action of nylidrin in the rat mast cell model is different from that of DSCG.

Animals↗

PubMed1983

Antiallergic activity of nylidrin hydrochloride (RHC 3432-A). II. A lack of correlation between inhibition of mediator release and levels of cyclic AMP.

Nylidrin hydrochloride has weak beta-adrenergic agonist properties with rat mast cells, and shows synergy with 3-isobutyl-1-methylxanthine (IBMX) in raising intracellular cAMP in purified mast cells; both of these properties can be blocked by dl-propranolol. However, the action of nylidrin hydrochloride as an inhibitor of histamine secretion from purified rat mast cells is not antagonized by dl-propranolol, nor is it potentiated by IBMX. Nylidrin-induced elevation of cellular cAMP in purified rat mast cells shows no correlation with nylidrin-induced inhibition of histamine release. Thus, nylidrin hydrochloride inhibits release of histamine from mast cells by a novel, non-adrenergic mechanism, which is not dependent on increased levels of cAMP.

Animals↗

PubMed1982

Beneficial hemorheologic therapy of chronic peripheral arterial disorders with pentoxifylline: results of double-blind study versus vasodilator-nylidrin.

Pentoxifylline (Trental 400 mg coated tablets) and nylidrin HCl 3 mg were compared for clinical efficacy and safety in an 8-week randomized double-blind trial. The study was conducted in patients with peripheral arterial disease (Fontaine stage II or III), with 30 patients receiving pentoxifylline (23 returned for follow-up), and 30 patients receiving nylidrin HCl (24 returned for follow-up). Efficacy was assessed objectively in terms of walking performance (absolute walking time and walking distance on a treadmill ergometer) and by acral plethysmography. The clear improvement shown for both variables was greater and statistically significant (p less than or equal to 0.05) after treatment with pentoxifylline. Laboratory data provided no evidence to suggest any adverse effect of either treatment. Subjective side effects were reported by six patients in the pentoxifylline group and by three patients in the nylidrin HCl group.

Adult↗

PubMed1980

Central cardiovascular effects of nylidrin (buphenine).

The injection of small doses of nylidrin into the vertebral artery lowered blood pressure in chloralose-anesthetized cats. Cerebroventricular perfusion of nylidrin also decreased blood pressure and inhibited or modified cardiovascular reflexes. There was inhibition of the reflex bradycardia evoked by i.v. noradrenaline or angiotensin. Likewise the pressure increase due to bilateral carotid occlusion was diminished. The blood pressure decrease elicited by stimulation of the central stump of a cut vagus nerve was inhibited or reversed. The pattern of central cardiovascular effects of nylidrin seemed not compatible with its well known beta-sympathomimetic properties. Indirect evidence points to an interasction with central alpha-receptors.

Adrenergic beta-Antagonists↗

PubMed1996

Growth and development until 18 months of children exposed to tocolytics indomethacin or nylidrin.

Indomethacin, a prostaglandin synthesis inhibitor, is a more efficient tocolytic than the beta-sympathomimetic nylidrin, but causes more frequent unwanted effects in the neonatal period. In order to elucidate the effects on neurodevelopment, infants randomly exposed in utero to either compound were followed up to 18 months. A total of 93 children (40 exposed to nylidrin and 53 exposed to indomethacin) were examined at the age of 12 months. A detailed neurological examination was carried out in 44 of these infants at the age of 18 months. At the age of 12 months the children in the indomethacin group showed poor outcome (death or severe BPD and/or CP and/or severe ROP) in 23% and the children in the nylidrin group in 5% (p = 0.039, Fisher Exact Test). Concerning the children born during tocolysis the corresponding figures were 73% and 13% respectively (p = 0.002, Fisher Exact Test). The growth of the children did not differ significantly between the two treatment groups. Neurological assessment at the age of 18 months revealed more subnormally scoring children in the indomethacin group, but the differences were not significant. It was concluded that the higher incidence of poor outcome and a lest favourable neurological development in the indomethacin group do not support indomethacin's position as the drug of choice for tocolysis.

Child Development↗

PubMed1979

Nylidrin HCL in the treatment of symptoms of the aged: a double-blind placebo controlled study.

This study was designed to assess the effectiveness and the safety of nylidrin HCL in the geriatric patient and mild to moderate symptoms of cognitive, emotional and physical impairment. Following a 3 week placebo washout, 60 patients received either nylidrin HCL or placebo for 12 weeks. Efficacy evaluations were made utilizing the Sandoz Clinical Assessment Geriatric (SCAG) Scale, a nurse's rating of ward behavior (SCASNO), the Hamilton Psychiatric Rating Scale for Depression, and 2 of the Katz Adjustment Scales. Significant improvement in symptom severity was demonstrated in the nylidrin group as compared to the placebo group. There were no abnormalities of clinical significance in the safety measurements and few side effects were reported.

Activities of Daily Living↗

PubMed1976

[Cardiovascular effects of nylidrin (Dilatol) in pregnancy].

8 normotensive late pregnant women were examined before, during and after the intravenous administration of nylidrin (Dilatol) with the method of quantitative sphygmometry, the bloodless graphic registration of the arterial blood pressure and the direct electronic timing of pulse wave velocity. Systolic blood pressure remains unchanged; mean and diastolic blood pressure and total peripheral resistance decrease. Simultaneously heart rate, stroke volume and above all cardiac output increase. The hemodynamic mode of action of nylidrin is a favourable one in regard to the perfusion of tissues in pregnancy, because the fall of total peripheral resistance is much more pronunciated than the decrease of blood pressure. Therefore there are no objections to a tocolytic treatment with nylidrin in normotensive pregnant women on the part of cardiovascular system.

Adult↗

PubMed1976

GLC determination of nylidrin in human urine samples.

A method for the detection of nanogram quantities of nylidrin in human urine is described. The method involves beta-glucuronidase hydrolysis, extraction with chloroform, derivatization by silylation, and GLC determination. The suitability of the method was tested by analysis of urine samples of subjects after oral ingestion of nylidrin hydrochloride.

Chromatography, Gas↗

PubMed1979

High-performance liquid chromatography of two peripheral vasodilators, nylidrin hydrochloride and isoxsuprine hydrochloride, in pharmaceutical dosage forms.

A reliable and selective high-pressure liquid chromatographic (HPLC) procedure for the quantitative determination of nylidrin hydrochloride or isoxsuprine hydrochloride in pharmaceutical dosage forms is described. The specificity of the stability-indicating HPLC procedure is presented for nylidrin hydrochloride.

Chromatography, High Pressure Liquid↗

PubMed1992

Urinary excretion of prostacyclin and thromboxane metabolites in threatened preterm labor: effect of indomethacin and nylidrin.

OBJECTIVE: We studied the role of smooth muscle-relaxing prostacyclin and its endogenous antagonist, thromboxane A2, in preterm labor by assessing the urinary output of the breakdown products of prostacyclin (6-keto-prostaglandin F1 alpha and 2,3-dinor-6-keto-prostaglandin F1 alpha) and those of thromboxane A2 (thromboxane B2, 2,3-dinor-thromboxane B2). STUDY DESIGN: Thirty-three women in preterm labor between 25 and 34 weeks of gestation were studied before, during, and after treatment with indomethacin (n = 16) or nylidrin (n = 17). Urinary prostanoid levels were determined by high-performance liquid chromatography followed by radioimmunoassay, and the excretion was expressed as nanograms of prostanoids per millimole of creatinine. Statistical analyses were done by paired and unpaired Student t test, by Spearman's correlation, and by Wilcoxon signed-rank test. RESULTS: Preterm labor was accompanied by a median 32% higher output of prostacyclin and thromboxane A2 metabolites as compared with those in 25 controls. At 8 hours after the start of treatment indomethacin induced maximal drops in 6-keto-prostaglandin F1 alpha (70%), in dinor-6-keto-prostaglandin F1 alpha (60%), in thromboxane B2 (85%), and in dinor-thromboxane B2 (95%) excretion. Within 1 week after the cessation of indomethacin, output of prostacyclin metabolites had recovered to pretreatment values, whereas output of thromboxane A2 metabolites was yet lower than the pretreatment value. Nylidrin induced no change in the output of prostacyclin and thromboxane A2 metabolites. CONCLUSION: Threatened preterm labor is associated with a rise in prostacyclin and thromboxane A2 synthesis. Indomethacin inhibits more thromboxane A2 than does prostacyclin synthesis. These findings may explain the fetal vascular changes during maternal indomethacin treatment.

6-Ketoprostaglandin F1 alpha↗

PubMed1991

Maternal plasma corticotrophin-releasing hormone--elevated in preterm labour but unaffected by indomethacin or nylidrin.

The role of corticotrophin-releasing hormone (CRH) in preterm labour was studied in 23 women in preterm labour at between 26 and 33 weeks gestation who were randomly allocated to receive treatment with indomethacin (n = 11) or with nylidrin a beta-sympathomimetic agent (n = 12). Maternal plasma CRH in the preterm group (median 70, range 9-597 pmol/l) before therapy was higher (P less than 0.05) than that in 23 control pregnancies, without uterine contractions, matched for gestational age (median 51, range 4-127 pmol/l). CHR levels determined after 3 and 24 h of treatment showed a 10% decrease in the indomethacin group and 10-20% decrease in the nylidrin group, but these changes were not statistically significant. After cessation of uterine contractions during tocolysis, 12 women proceeded to give birth preterm (less than 37 weeks) and their pretreatment CRH levels (median 195, range 9-597 pmol/l) were higher (P less than 0.05) than those in women whose pregnancy proceeded to term (median 52, range 16-207 pmol/l). In another group of women, full-term labour was not accompanied by any changes in maternal CRH levels. Umbilical plasma CRH levels were 1.1-9.8% of the paired maternal levels and did not rise with advancing gestational age. Nor had the type of delivery (elective caesarean section before labour, or preterm or term vaginal delivery) any effect on fetal CRH levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1979

Efficacy of nylidrin hydrochloride in the treatment of cognitive impairment in the elderly.

A double-blind study was conducted on the effects of nylidrin hydrochloride versus placebo in 60 patients with mild to moderate symptoms of chronic brain syndrome. Their ages ranged from 65 to 99 years. Preliminary results indicated that nylidrin HCl (a vasodilator) is a relatively safe therapeutic agent and more effective than placebo in ameliorating the symptoms of cognitive impairment associated with aging, on both a short term (3-month) and a long-term (9-month) basis. In a dosage of 24 mg daily, it reached its peak effectiveness after 3 months of use.

Aged↗

PubMed1991

Catechol-O-methyltransferase activity in red blood cells in threatened preterm labor; effect of indomethacin and nylidrin.

Catecholamines that are released in excess during human labor are inactivated mainly by catechol-O-methyltransferase (COMT). To ascertain whether uterine contractions are associated with changes in COMT activity in red blood cells (RBCs), we studied 25 women with established threat of preterm labor between 25 and 33 weeks of gestation, 25 gestational age-matched control women not experiencing uterine contractions, 25 women who were in term labor, and 25 non-pregnant healthy women. COMT activity in pregnant women without uterine contractions (median 0.3, range 0.1-0.8 pmol/mg/min) was lower (p less than 0.05) than that in non-pregnant control series (median 0.5, range 0.3-0.7 pmol/mg/min). RBCs' COMT activity in women with preterm labor (median 0.6, range 0.2-1.1 pmol/mg/min) was greater (p less than 0.05) than that in pregnant and non-pregnant control women, but similar to that during term labor (median 0.5, range 0.2-1.7 pmol/mg/min). Women with preterm labor were treated with indomethacin (12 women) or nylidrin (13 women). Nylidrin treatment was accompanied by a 35% rise in COMT activity 3 h later, whereas indomethacin caused no significant change. Apart from cessation of uterine contractions during tocolysis, 13 women went into labor before the 37th gestational week, but their pretreatment COMT activity (median 0.7, range 0.2-1.1 pmol/mg/min) did not differ from COMT activity in women whose pregnancy proceeded to term (median 0.5, range 0.3-1.0 pmol/mg/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗