Protective role of naftidrofuryl against methotrexate-induced testicular damage via the amelioration of the p53/miRNA-29a/CDC42 apoptotic pathway, inflammation, and oxidative stress

This study aimed to assess the possible protective effects of naftidrofuryl (Naf) against methotrexate (MTX)-induced testicular toxicity in rats. Male rats were randomly distributed into four groups: control, Naf, MTX, and MTX+Naf groups. MTX administration induced oxidative stress, inflammation, and apoptosis in the testicular tissue, while pretreatment with Naf attenuated these pathways. Naf pretreatment significantly decreased malondialdehyde and interleukin-6 contents, microRNA-29a (miRNA-29a) expression level, and nuclear factor kappa B and p53 immunostaining in the testicular tissues compared to the MTX group. Conversely, it significantly increased Johnsen's score, serum testosterone level, serum total antioxidant capacity, testicular superoxide dismutase activity, testicular catalase activity, and testicular cell division cycle 42 (CDC42) expression compared to the MTX group. In conclusion, Naf exerted a significant protective effect against MTX-induced testicular toxicity via antioxidant and anti-inflammatory mechanisms and modulating the p53/miRNA-29a/CDC42 apoptotic pathway.

The vasodilator naftidrofuryl attenuates short-term brain glucose hypometabolism in the lithium-pilocarpine rat model of status epilepticus without providing neuroprotection

Status epilepticus (SE) triggered by lithium-pilocarpine is a model of epileptogenesis widely used in rats, reproducing many of the pathological features of human temporal lobe epilepsy (TLE). After the SE, a silent period takes place that precedes the occurrence of recurrent spontaneous seizures. This latent stage is characterized by brain glucose hypometabolism and intense neuronal damage, especially at the hippocampus. Importantly, interictal hypometabolism in humans is a predictive marker of epileptogenesis, being correlated to the extent and severity of neuronal damage. Among the potential mechanisms underpinning glucose metabolism impairment and the subsequent brain damage, a reduction of cerebral blood flow has been proposed. Accordingly, our goal was to evaluate the potential beneficial effects of naftidrofuryl (25 mg/kg i.p., twice after the insult), a vasodilator drug currently used for circulatory insufficiency-related pathologies. Thus, we measured the effects of naftidrofuryl on the short-term brain hypometabolism and hippocampal damage induced by SE in rats. 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography (PET) neuroimaging along with various neurohistochemical assays aimed to assess brain damage were performed. SE led to both severe glucose hypometabolism in key epilepsy-related areas and hippocampal neuronal damage. Although naftidrofuryl showed no anticonvulsant properties, it ameliorated the short-term brain hypometabolism induced by pilocarpine. Strikingly, the latter was neither accompanied by neuroprotective nor by anti-inflammatory effects. We suggest that naftidrofuryl, by acutely enhancing brain blood flow around the time of SE improves the brain metabolic state but this effect is not enough to protect from the damage induced by SE.

Comparison of Cilostazol and Naftidrofuryl in an Experimental Acute Ischemia-Reperfusion Model

INTRODUCTION

Naftidrofuryl and cilostazol are drugs with proven efficacy in the treatment of claudication in peripheral vascular disease. In this experimental study, we evaluated the effects of naftidrofuryl and cilostazol in ischemia-reperfusion (IR) injury on various tissues.

MATERIALS AND METHODS

40 male albino Wistar rats (8-12 weeks old, 250-350 g.) are randomly divided into 4 groups: Control (Group 1), sham (group 2), cilostazol pre-treatment (group 3), naftidrofuryl pre-treatment (group 4). During 21 days placebo is given to group 2, 12 mg/kg/day cilostazol is given to group 3, 50 mg/kg/day naftidrofuryl is given to group 4 orally. Ischemia and reperfusion are induced at the lower hind limb in Groups 2, 3 and 4. Ischemic muscle, kidney, liver, heart, brain and blood samples are obtained. The total antioxidant capacity, oxidant levels and oxidative stress index are studied for each group.

RESULTS

Both drugs have protective effects of remote organ injury following IR. Systemic effects are similar to each other, both have protective effects of IR injury. It showed no statistical significance in the total antioxidant capacity. Total oxidant levels are significantly affected by cilostazol in the heart (p < 0.01) and by naftidrofuryl in the liver (p < 0.01). The effect on oxidative stress was only significant with cilostazol on the heart (p < 0.01).

CONCLUSION

Cilostazol and naftidrofuryl had beneficial effects in all tissues against tissue damage caused by IR injury. In ischemic muscle, kidney and heart cilostazol had improved outcomes comparing to naftidrofuryl. Naftidrofuryl had benefits over cilostazol in liver tissue.

[Use of naftidrofuryl in angiology]

The review analyses the role of serotonin in the development of pathological processes in angiological patients, showing its negative role in aggravating chronic and acute ischaemia of various organs (brain, myocardium, extremities) both at the expense of vasoconstriction and due to an increase in blood platelet aggregation of blood platelets and erythrocytes, followed by analysis of clinical efficacy of naftidrofuryl) - serotonin 5-HT2 receptor antagonist. Results of numerous randomized trials confirmed its efficacy and safety in treatment of angiological patients, being superior to other vasotropic drugs (cilostazol, pentoxyphyllin, nicotinic acid).

Naftidrofuryl

Naftidrofuryl (Praxilene) is a vasodilator that has been used in the treatment of intermittent claudication for >30 years in Europe to improve walking distance and provide symptomatic relief. However, earlier trials had inconsistencies in design and the clinical relevance of the treatment effect has been controversial. Recent randomised, double-blind, placebo-controlled trials, however, have generally been conducted in accordance with updated methodology guidelines. In these studies, naftidrofuryl 200mg three times daily improved pain-free and maximal walking distances and health-related quality of life by a significantly greater extent than placebo in patients with intermittent claudication. The magnitude of these effects appears to support claims that the effects of naftidrofuryl are clinically relevant in these patients.

Calcium oxalate deposition in renal allografts: morphologic spectrum and clinical implications

Many aspects of calcium oxalate (CaOx) deposition in renal transplant biopsies are not known. Review of all renal transplant biopsies performed in a 7-year period showed that CaOx deposition could be classified into three groups. Group I: Seven biopsies within a month post-transplant displayed rare CaOx foci against a background of acute tubular necrosis or acute cell-mediated rejection. At follow-up, five grafts functioned well and two failed due to chronic allograft nephropathy. CaOx in this context was an incidental finding secondary to a sudden excretion of an end-stage renal disease-induced increased body burden of CaOx. Group II: Two biopsies performed 2 and 10 months post-transplant showed rare CaOx foci against a background of chronic allograft nephropathy, leading to graft loss. CaOx in this context reflected nonspecific parenchymal deposition due to chronic renal failure regardless of causes. Group III: One biopsy with recurrent PH1 characterized by marked CaOx deposition associated with severe tubulointerstitial injury and graft loss 6 months post-transplant. There were two previously reported cases in which CaOx deposition in the renal allografts was due the antihypertensive drug naftidrofuryl oxalate or increased intestinal absorption of CaOx. CaOx deposition in renal allografts can be classified in different categories with distinctive morphologic features and clinical implications.

Characterization of the CNS effects of naftidrofuryl (Praxilène) by quantitative EEG and functional MRI: a study in healthy elderly subjects

In the present study, we investigated the effects of a single and a repeated (5 days) administration of naftidrofuryl, a serotonin 5-HT2 receptor inhibitor having neuroprotective properties, on functional brain physiology in male healthy elderly subjects, using quantitative electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twelve subjects aged 60 +/- 3.8 years completed the quantitative EEG study, where the effects of 400 and 600 mg were assessed, and 12 other subjects (aged 56 +/- 4.7 years) completed the fMRI study, where the effect of 400 mg was assessed on the brain activation induced by the continuous performance test (CPT). Naftidrofuryl induced a transient reduction in alpha activity followed by a specific synchronisation of the 9.5- to 11-Hz EEG activity most pronounced after repeated administration. Such regimen also increased the CPT-induced brain activation visualized by way of fMRI. The results of the present study can be interpreted at the functional level that naftidrofuryl induced an improved level of vigilance or an increased capacity of alertness in healthy elderly subjects.

Effect of naftidrofuryl on intramuscular partial oxygen pressure (pO2) prior to, during and after physical load on the treadmill in apparently healthy subjects

Previous studies demonstrated that naftidrofuryl increased the cutaneous and intramuscular tissue pO2 at rest. The presented open prospective pilot study is to investigate in apparently healthy subjects (n=12) whether naftidrofuryl also affects pO2 in situations of muscular stress. The pO2 is measured with a flexible probe in the anterior tibial muscle during treadmill exercise prior to and after one-week treatment with 100 mg of naftidrofuryl administered three times a day. The intake of naftidrofuryl proved to significantly affect the intramuscular partial oxygen pressure. With 38.6+/-22.9 mmHg, the pO2 is at rest already significantly (p<0.05), i.e., approx. 40% higher after one week of intake than before treatment (27.3+/-12.1 mmHg). This higher pO2 level is maintained during exercise. The higher the physical load, the larger the difference in pO2. While under naftidrofuryl treatment the measured pO2 values exhibit the tendency to increase during the first exercise phase (at a load of 3 km/h and a gradient 5 degree), the differences are even significant under higher physical stress (at 5 km/h and a gradient of 10 degree). With 33.9+/-12.0 mmHg the mean minimum pO2 determined at the higher load level still ranges above the basal pO2 measured before the start of naftidrofuryl treatment.

Naftidrofuryl-driven regulation of endothelial ICAM-1 involves nitric oxide

Naftidrofuryl is a selective inhibitor of the 5-HT2 receptor expressed on human endothelial cells. This drug has been used over the years to cope with cerebral or peripheral ischemic accidents; however, no clear mechanism of action of this molecule has been highlighted to explain its vascular effects. In the present work, we demonstrate that the involvement of nitric oxide can account for the effects of naftidrofuryl. Indeed, naftidrofuryl potently inhibited the TNF-alpha-triggered increase of intercellular adhesion molecule-1 (ICAM-1) expression as well as stress fiber formation in human umbilical vein endothelial cells (HUVEC). Moreover, naftidrofuryl induced the expression of type II nitric oxide synthase (NOS II) messenger and protein, leading to a noticeable increase in nitric oxide synthesis. Furthermore, using the specific NOS II inhibitor 1400W, we verified that the observed effects of naftidrofuryl were NOS II-dependent. The biology of nitric oxide accounts for the reduction of the vasospasm associated with stroke and the strong inhibition of platelet aggregation. In conclusion, our work provides evidence for the inhibition of leukocyte recruitment by downregulation of CD54/ICAM-1, an additional key factor to be dealt with during thrombotic accidents. Importantly, it also highlights a novel NOS II-dependent mechanism of action for naftidrofuryl.

Reduction of endothelin-1 binding and inhibition of endothelin-1-mediated detrusor contraction by naftidrofuryl

Endothelin-1 (ET-1) causes urinary bladder smooth muscle contraction and the endothelin receptors A and B (ET(A) and ET(B)) are both known to be present in the rabbit urinary bladder. Alterations in ET-1 signalling have been implicated in the pathophysiology of urinary tract disorders secondary to bladder outlet obstruction and also in diabetic cystopathy. Naftidrofuryl (Naf) (marketed under the trade name Praxilene) improves walking distance in patients with peripheral vascular disease, an effect which may be partially attributed to ET-1 antagonism. The purpose of this study is to assess whether Naf will reduce ET-1 binding in the rabbit detrusor muscle and to assess whether there is inhibition of ET-1-mediated detrusor contraction. Detrusor smooth muscle strips were mounted in organ baths and cumulative response curves were measured for ET-1-mediated contractions in the presence and absence of 10(-6) M Naf (therapeutic concentration). In addition, ET-1 was added to the detrusor strips in the presence of the ET(A) antagonist, BQ123, and the ET(B) antagonist, BQ788, to identify the receptor subtype functionally involved. Overall inhibition of [(125)I]ET-1 binding by Naf was assessed using autoradiography. Identification of receptor-subtype binding reduction was assessed using the radioligands [(125)I]PD151242 and [(125)I]BQ3020. Naf inhibited ET-1-mediated detrusor contractions significantly (P<0.04), e.g. at 10(-10) M ET-1, contraction was completely abolished by Naf. Autoradiography indicated that Naf competitively inhibited [(125)I]ET-1 binding in a dose-dependent manner (IC(50)=3x10(-7) M). All radioligand binding was reduced indicating binding of Naf to both ET(A) and ET(B) receptors. Naf reduces binding of ET-1 to rabbit detrusor ET(A) and ET(B) receptors and inhibits ET-1-induced detrusor contractions mediated by ET(A) receptors. Naf may have therapeutic potential in the treatment of bladder disorders secondary to bladder outlet obstruction and diabetes mellitus.

Vitamin A metabolism is altered in brown Norway and long-Evans rats infused with naftidrofuryl or erythromycin intravenously

Enzymatic retinyl ester hydrolysis is a key reaction for maintaining cellular retinol homeostasis. The ability of naftidrofuryl and erythromycin to inhibit retinol liberation by retinyl ester hydrolase (REH) in vitro suggests an ability to interfere with vitamin A metabolism in vivo, particularly during hepatic processing. To address this question, systemic and local response to these agents were studied in Brown Norway (BN) and Long-Evans (LE) rats. The study was conducted in two parts: a drug-loading phase and a washout phase. Analysis of variance of the time course changes in plasma retinol during the post-treatment period (Days 10-18) showed rat strain (p < 0.04) and time (p < 0.001; strain-by-time interactive effect, p < 0.001) to be significant factors, but drug exposure (p = 0.19) was not significant. Endpoints included hepatic REH activity, size and composition of the liver vitamin A stores, and retinoid content of the kidneys. Rats recovering from naftidrofuryl dosing demonstrated a lower REH activity than did animals recovering from erythromycin treatment (p < 0.009). The major side effect of erythromycin is vitamin A accumulation in the liver (p < 0.001) and reductions in retinol reserves (p < 0.02) were among the consequences of naftidrofuryl treatment. In the kidney of LE rats, there were higher concentrations of vitamin A (p < 0.003) secondary to naftidrofuryl exposure. Together our data suggest that clinically achievable concentrations of the drugs, given as a continuous infusion, produce aberrations in vitamin A metabolism.

Naftidrofuryl exerts antiserotonergic but no endothelin-receptor blocking effects in AS4.1 cells, juxtaglomerular cells and isolated perfused rat kidneys

Naftidrofuryl, a 5-hydroxytryptamine 2 (5-HT 2 ) serotonergic receptor antagonist with vasodilator effects, has successfully been used for intermittent claudication, some forms of dementia, and glaucoma. Recently, an additional mode of action of naftidrofuryl (i.e., mixed endothelin receptor antagonism) has been suggested. However, in the current study naftidrofuryl was unable to block endothelin-3-induced free intracellular calcium increases, in contrast to a mixed endothelin receptor antagonist, bosentan. The inhibition of forskolin-induced renin secretion by endothelin-3 in primary cultures of mouse juxtaglomerular cells and by endothelin-1 in the isolated perfused rat kidney could not be blocked by naftidrofuryl. Naftidrofuryl was unable to block marked endothelin-1-induced renal vasoconstriction in isolated perfused rat kidney. In contrast, naftidrofuryl markedly attenuated serotonin-induced renal vasoconstriction and nearly completely blocked serotonin's renin inhibitory properties in isolated perfused rat kidney. The present results suggest that naftidrofuryl is a potent antagonist of serotonin's renal effects, but has no endothelin receptor-blocking properties.

[Deleterious cardiac effects of serotonin in myocardial ischemia: role of naftidrofuryl]

It is now accepted that serotonin can either initiate or aggravate myocardial ischaemia through a vasoconstrictor action and platelet activation. It is therefore possible that substances likely to neutralize the effects of serotonin could be used, without any danger, in humans with ischaemic heart disease. This type of action may therefore be exerted by 5-HT2 antagonists, such as naftidrofuryl. A recent double-blind clinical study has in fact shown that administration of naftidrofuryl versus placebo leads to better exercise tolerance, with an increase in the maximum level and delay in ST segment shift (increase in the threshold of onset of ischaemia). The purpose of this study was therefore to evaluate, in an animal model (pig) of acute myocardial ischaemia (occlusion of the proximal section of the left anterior descending coronary artery), the action of serotonin, naftidrofuryl and a combination of both substances on the following parameters: 1) electrophysiological (sinus heart rate, ST segment shift, T-wave amplitude, duration of monophasic action potentials, intraventricular conduction time); 2) haemodynamic (systolic, diastolic and mean blood pressure, first derivative of rate of increase of left ventricular pressure with time: LV dP/dt max); and 3) biochemical (malonedialdehyde concentration as an index, cell peroxidation index, creatine phosphate and adenosine triphosphate). It was found that co-infusion of serotonin aggravated the myocardial ischemia and that naftidrofuryl exerted beneficial effects on the serotonin-mediated aggravation of myocardial ischaemia.

A new study demonstrates the efficacy of naftidrofuryl in the treatment of intermittent claudication. Findings of the Naftidrofuryl Clinical Ischemia Study (NCIS)

BACKGROUND

The efficacy and safety of naftidrofuryl were assessed in a double blind, placebo controlled, parallel group study, in patients presenting with intermittent claudication, according to the latest European guidelines.

METHODS

The outpatients selected were of both sexes, aged 35 to 85, with moderately severe chronic, stable intermittent claudication and a pain-free (PFWD) and maximum walking distance (MWD) on the treadmill of between 100 and 300 metres. They received naftidrofuryl 200 mg tid or placebo for six months and were then assessed during a six-month follow-up period without treatment. The primary outcome measures were the pain-free walking distance and maximum walking distance.

RESULTS

Of the 221 selected patients, 196 were randomised and 181 entered the intention-to-treat analysis. The two groups were well matched for demographic variables, risk factors and history of vascular disease. After six months of treatment, patients who received naftidrofuryl had a 92% im-provement of geometric pain-free walking distance versus 17% in the placebo group (p < 0.001) and an 83% improvement of geometric maximum walking distance versus 14% in the placebo group (p < 0.001). During the follow-up period without treatment, the walking distances of the patients in the naftidrofuryl group significantly decreased. The incidence of adverse events was similar in the two groups.

CONCLUSIONS

This study demonstrated the efficacy of naftidrofuryl versus placebo in patients with intermittent claudication with a highly significant and clinically relevant difference and confirmed its good safety profile.

Effect of naftidrofuryl on platelet aggregation in plasma from aspirin treated patients: an in vitro study

This study concerns an in vitro evaluation of the effect of naftidrofuryl on platelet aggregation in plasma of 15 diabetic patients, who were being treated with aspirin, and who were suffering from chronic arterial disease of the lower limbs. Platelet aggregation, induced either spontaneously or by aggregating agents, was measured in platelet-rich plasma (PRP). The results show that serotonin (5-HT)- and adenosine 5'-diphosphate (ADP)-induced platelet aggregation significantly decreased after addition of naftidrofuryl. Decreases were achieved with naftidrofuryl at a low dose (0.06 microM) and became more marked with naftidrofuryl at higher concentrations. In contrast, naftidrofuryl did not appear to modify routinely spontaneous platelet aggregation. These results show an in vitro antiaggregating effect of naftidrofuryl on platelets of aspirinized patients. However, the clinical interest of a such coadministration of naftidrofuryl and aspirin in patients, has still to be confirmed in a double blind randomized trial.

Effect of endothelin-1 on human platelet shape change: reversal of activation by naftidrofuryl

Naftidrofuryl (Praxilene; NAF) significantly improves claudication distance in patients with peripheral vascular disease (PVD). Endothelin-1 (ET-1) is a powerful endogenous vasoconstrictor and the circulating levels of ET-1 are elevated in patients with vascular disease. Platelet rich plasma (PRP) was prepared from healthy volunteers. NAF at concentrations similar to therapeutic levels (3.5-14 micromol/l), inhibited (P < 0.02) platelet activation (as indicated by a fall in median platelet volume, MPV) induced by ET-1 (0.4 micromol/l) alone. NAF also inhibited (P <0.0001) shape change (PSC; an early phase of platelet activation, characterised by an increase in MPV) induced by ET-1 (0.4 micromol/l) in combination with ADP (0.05-0.15 micromol/l) or serotonin (0.03-0.13 micromol/ l). We assessed the effect of ET(A) (BQ123, 50 nmol/l) or ET(B) (BQ788, 50 nmol/l) receptor antagonists on PSC induced by ET-1 alone. Both antagonists significantly inhibited PSC. We conclude that ET-1 activates human platelets. Both ET(A) and ET(B) receptors probably contribute to this response by a complex mechanism that requires further elucidation. NAF antagonises the action of ET-1 on human platelets. These actions may contribute to the beneficial effects of NAF in PVD.

The effect of blood flow promoting drugs on cochlear blood flow, perilymphatic pO(2) and auditory function in the normal and noise-damaged hypoxic and ischemic guinea pig inner ear

The effect of blood flow promoting drugs, such as hydroxyethyl starch (HES) either of low or high molecular weight (HES 70, HES 200), pentoxifylline, ginkgo biloba, naftidrofuryl and betahistine, and various combinations of the drugs was studied in unexposed and noise-exposed (broad-band noise, bandwidth 1-12 kHz, 106 dB SPL, 30 min) guinea pigs. The results were compared without therapy and placebo (isotonic saline, NaCl). The cochlear blood flow (CoBF) and the partial pressure of oxygen in the perilymph (PL-pO(2)) were continuously and simultaneously recorded over a period of 210 min. In addition, cochlear microphonics (CMs), compound action potentials of the auditory nerve (CAPs) and auditory brain stem responses (ABRs) were registered. Noise-induced hearing loss (NIHL) paralleled a decrease of PL-pO(2). Both were found to occur before evidence of reduced CoBF. PL-pO(2) and CoBF declined progressively post-exposure, while CMs, CAPs and ABRs showed no further deterioration or signs of recovery up to 180 min after cessation of noise. Treatment started 60 min post-exposure, respectively after 90 min, without manipulation in unexposed animals, and was then studied for a further 120 min. In unexposed animals, CoBF increased significantly during infusion of HES 70, HES 200, pentoxifylline and betahistine. NaCl, ginkgo biloba and naftidrofuryl did not alter CoBF. PL-pO(2) decreased significantly during infusion of all administered drugs and combinations, except for NaCl. CMs, CAPs and ABRs remained constant, with the exception of increased ABRs after infusion of HES 70 and HES 200. In noise-exposed animals, a sustained therapeutic effect on cochlear ischemia was achieved only by HES 200 and pentoxifylline. HES 70, betahistine and ginkgo biloba compensated cochlear ischemia only during infusion; however, 30-60 min after termination of therapy, no significant difference of values for CoBF was observed compared to the untreated noise-exposed groups. NaCl and naftidrofuryl showed no effect on CoBF. None of the applied drugs had a sustained compensatory effect on cochlear hypoxia. CMs, CAPs and ABRs improved significantly after HES 70, HES 200 and betahistine, resulting in partial recovery of CMs, and partial (betahistine) or even full (HES 70 and HES 200) recovery of CAPs and ABRs. In contrast, NaCl, pentoxifylline, ginkgo biloba and naftidrofuryl had no therapeutic effect on NIHL.

[Evaluation of the efficacy and tolerance of naftidrofuryl in patients presenting with exertional angina. Multicenter double-blind versus placebo study]

Due to its vascular and platelet 5-HT2 receptor antagonist properties and its metabolic properties, naftidrofuryl specifically counteracts local ischaemic phenomena. One of its major indications is the treatment of intermittent claudication, but it is well known that peripheral arterial disease is the sign of diffuse arterial disease, associated with particularly lethal coronary disease. Recent studies increasingly implicate serotonin (5-HT) in coronary ischaemic processes. In view of the similarities between these pathophysiological data and the characteristics of this molecule, we decide to evaluate the coronary protection afforded by naftidrofuryl and its safety. This multicentre double-blind placebo-controlled study was conducted in 51 patients over a period of one month. Inclusion criteria were stable angina with an electrically positive stress test, despite antianginal treatment either by beta-blocker or by calcium channel blocker. Follow-up comprised clinical assessment and a stress test on inclusion and at 1 month. The groups were comparable on inclusion. Overall, the results showed a greater improvement with naftidrofuryl than with reference treatment for all parameters studied. Significant differences were observed in favour of the verum group for time to onset of ST depression, the maximum level reached, the number of stress tests which became negative and the patient's global assessment. No problems of interaction with concomitant treatments, particularly beta-blockers, calcium channel blockers or antiarrhythmics was observed. This study shows that naftidrofuryl allows improvement of ergometric parameters and especially elevation of the ischaemic threshold on exertion.

Behavioral studies of the effects of moderate oligemic hypoxia caused by bilateral clamping of carotid arteries in mice. Impairment of spatial working memory

The experiments carried out on Albino Swiss mice indicated that bilateral clamping of carotid arteries (BCCA) for 30 min caused no neuronal damage but produced an increase in GABA content in the hippocampus, striatum and frontal cortex. The behavioral studies have shown that BCCA did not influence the motor coordination, the spontaneous locomotor activity, the reactivity to pain and the cataleptic response to haloperidol of the mice. However, a significant increase in amphetamine-induced hyperactivity was observed after BCCA. In mice, BCCA did not impair long-term memory and spatial working memory, reflected by alternation behavior in the Y-maze. The same dose of scopolamine impaired the working memory in mice which underwent BCCA much more than sham-operated controls. Naftidrofuryl improved the working memory in mice subjected to BCCA as measured 48 h after the surgery. Pretreatment with naftidrofuryl protected the animals against the impairment of alternation behavior caused by scopolamine administration.

Protection against light-induced retinal degeneration with naftidrofuryl (Praxilene) in the rat

The purpose of this work was to investigate the ability of Naftidrofuryl (Praxilene, Lipha-Santé, France) to produce light-induced retinal degeneration in the rat. Fisher male rats were injected intraperitoneally with 30 mg/kg Naftidrofuryl in 0.9% NaCl. The first injection took place 30 minutes before the beginning of the constant light exposure (90 fc) and was repeated at days 2 and 4. The animals were sacrificed at day 7. Controls treated or not with Naftidrofuryl were exposed to a regular cyclic light environment (20 fc). Eyes were fixed in 4% paraformaldehyde and embedded in Historesin. Whole median 5 microns sections of the retina were analyzed by measurement of the thickness of the retinal photoreceptor nuclear and inner and outer segment layers with a Biocom image analyzer. After one week of constant illumination, the photoreceptor nuclear layer thickness decreased in all regions of the retina, more in the superior than in the inferior region. In animals treated with Naftidrofuryl, a significant rescue from degeneration was observed throughout all retinal regions. An average rescue of 66% (compared with the retina from constantly illuminated rats) was observed. Naftidrofuryl had no effect on cyclic light-raised rats. Naftidrofuryl partially protects against the degeneration of photoreceptors induced by constant light illumination of the rat retina.

Effects of delayed treatment with nafronyl oxalate on microsphere embolism-induced changes in monoamine levels of rat brain regions

1. The present study was undertaken to examine the effects of delayed treatment with nafronyl oxalate (nafronyl), a cerebral vasodilator, on monoamine neurotransmitters of brain regions in the microsphere-embolized rat. 2. Microsphere embolism was induced by injecting 900 microspheres with a diameter of 48 microns into the right internal carotid artery of rats. Microsphere-embolized rats were treated with nafronyl, 15 mg kg-1, i.p., twice daily from the first to the 5th day. Levels of monoamines and their metabolites in the cerebral cortex, striatum, and hippocampus were measured on days 3 and 5 after the operation by a high-performance liquid chromatograph with electrochemical detection. In vivo tyrosine or tryptophan hydroxylation was estimated by measurement of the accumulation of 3, 4-dihydroxyphenylalanine or 5-hydroxy-1-tryptophan after administration of 3-hydroxybenzylhydrazine dihydrochloride, an inhibitor of aromatic L-amino acid decarboxylase. 3. Microsphere embolism induced decreases in dopamine, noradrenaline and 5-hydroxytryptamine in three brain regions of the right hemisphere on days 3 and 5. In the left hemisphere, the monoamines were reduced, but to a lesser degree than in the right hemisphere. On days 3 and 5, the decrease in the monoamines of the right hemisphere was attenuated by nafronyl treatment except for noradrenaline on day 3. The decrease in the monoamines levels in the left hemisphere was almost completely prevented by nafronyl treatment. 4. On day 3 after microsphere embolism, in vivo tyrosine and tryptophan hydroxylation was lower than the pre-embolic value in all three brain regions. Treatment of the embolized rats with nafronyl significantly attenuated the decrease in in vivo tyrosine and tryptophan hydroxylation in the ipsilateral hemisphere, but not hippocampal tryptophan hydroxylation. 5. The results suggested that treatment with nafronyl improves or attenuates changes in monoamine neurotransmitter metabolism of the brain regions impaired by microsphere embolism. The mechanisms underlying this effect may be attributed to preservation of the ability to synthesize monoamines when the brain is ischaemic or oligaemic.

Oral naftidrofuryl. A review of its pharmacology and therapeutic use in the management of peripheral occlusive arterial disease

Naftidrofuryl has been used for the treatment of intermittent claudication, a symptom of mild to moderate peripheral occlusive arterial disease (POAD), for at least 2 decades. As a serotonin 5-HT2 receptor antagonist, naftidrofuryl has vasoactive properties in addition to its favourable effects on oxidative metabolism, peripheral transcutaneous oxygen pressure and the rheological properties of platelets and erythrocytes. The drug may also reduce hypercholesterolaemia-induced intimal proliferation. Clinical trials which conform best with European guidelines have shown that 3 and 6 months' oral therapy with naftidrofuryl 600 or 633 mg/day (in 3 or 2 divided doses) increased pain-free walking distance to a greater extent than placebo administration in patients with POAD. Surgical revascularisation was required less often during 6 months of therapy with naftidrofuryl than in placebo recipients, confirming the superiority of naftidrofuryl treatment compared with placebo. Available data provide some evidence of efficacy of the drug in the treatment of ischaemic rest pain and vascular ulceration. However, further trials are required before the usefulness of oral naftidrofuryl in severe POAD can be fully established. When given orally, naftidrofuryl is well tolerated. Mild gastrointestinal effects are the most common adverse events, requiring withdrawal of therapy in approximately 1.2% of patients compared with 0.95% of placebo-treated patients. In summary, oral naftidrofuryl improves the symptoms of intermittent claudication in patients with POAD with minimal risk of adverse effects. Therefore, in patients with Fontaine's classification stage II POAD for whom lifestyle modifications and management of concomitant disease have provided insufficient benefit, naftidrofuryl is potentially useful.

Microvascular disease and anastomotic dehiscence in the colon

Platelet-derived serotonin released in response to tissue manipulation during surgery may contribute to mesenteric arterial vasospasm leading to postoperative anastomotic leakage after colorectal resection. Organ bath experiments were used to demonstrate the efficacy of naftidrofuryl fumarate (NFT) to oppose serotonin-induced vasoconstriction of human mesenteric arteries. Cumulative dose-response curves were derived with and without NFT at 10(-9) and 10(-6) mol/l concentrations. The difference in maximal contractility between the three sets of curves (n = 8 for each) was significant (P < 0.0001). Sensitivity to serotonin in each of the three curves was measured by calculating the concentration for half-maximal response; differences were again significant (P < 0.0001). NFT reduced serotonin-induced contractility in a dose-dependent fashion in rings of human mesenteric arteries in vitro. This suggests a possible role for NFT in reducing mesenteric vasospasm in colorectal surgery.

Antiatherosclerotic effects of oral naftidrofuryl in cholesterol-fed rabbits involve inhibition of neutrophil function

We investigated the action of oral naftidrofuryl, a serotonin (5-HT2)antagonist, on atheromatous plaque formation, endothelial function, and neutrophil activity in cholesterol-fed (1% for 12 weeks) rabbits. Cholesterol feeding caused almost complete (84 +/- 4%) coverage of the aortic surface with atheromas and a marked intimal thickening. The endothelium-dependent relaxation to acetylcholine (ACh 1 nM-10 microM) and substance P (30 nM) was considerably reduced, whereas the relaxing effect to the endothelium-independent nitric oxide donor linsidomine (SIN-1) (100 microM) was unchanged. Treatment of hypercholesterolemic rabbits with naftidrofuryl (50 mg/kg body weight) resulted in a marked (54 +/- 6%, p < 0.05) reduction in aortic plaque formation. Endothelium-dependent relaxation to ACh was significantly improved in rings of both thoracic aorta: 33 +/- 5 versus 14 +/- 5% (p < 0.05) and abdominal aorta 68 +/- 9 versus 37 +/- 10% (p < 0.05). Similar results were obtained with substance P, but the responses to SIN-1 were unchanged. Zymosan-induced, luminol-enhanced chemiluminescence of polymorphonuclear leukocytes (PMN) was markedly stimulated in cholesterol-fed rabbits. Naftidrofuryl reduced this hyperreactivity to that of control rabbits. There was no change by naftidrofuryl in any of these parameters in control rabbits, precluding a direct action of the compound in nonhypercholesterolemic conditions. These data demonstrate significant endothelium-protective actions of long-term oral naftidrofuryl in cholesterol-fed rabbits that involve inhibition of cholesterol-induced neutrophil activation.

Platelet aggregation after naftidrofuryl application in vitro and ex vivo

Naftidrofuryl has been shown to inhibit the interaction between platelets and damaged endothelium, which may lead to thrombosis and is mediated by the 5-hydroxytryptamine. (5-HT2) receptor. This study was designed to investigate the effects of naftidrofuryl on 5-HT induced platelet aggregation. In vitro experiments were carried out on platelets from healthy laboratory personnel. Naftidrofuryl (0.0625-100 microM) caused a continual increase in in vitro inhibition, whereby the inhibition at 0.0625 microM was already significant when compared to control (p < 0.05). The IC50 was approximately 10 microM induced aggregation. Subsequently, ex vivo effects of naftidrofuryl on 5-HT induced platelet aggregation of healthy volunteers together with naftidrofuryl plasma levels were measured. Twelve healthy volunteers received either 400 mg naftidrofuryl or placebo in this double-blind, crossover study. Blood samples for determination of aggregation and naftidrofuryl plasma levels were taken before, 0.5, 1, 2, 3, 4, 5, 6.5 and 9 h after medication application. One hour after application of 400 mg naftidrofuryl a maximal plasma level of approximately 380 ng/ml was measured. Under control conditions the aggregation (Vmax) increased from an arbitrary 100% at 8:00 am to about 150% by 10:00 am, remaining at this level until 5:00 pm. Application of 400 mg naftidrofuryl p.o. resulted in a 50% decrease in Vmax 2 h after drug application. Thereafter, the aggregation rose to the initial 100% value 4 h after drug application and remained at this level during the observation period.(ABSTRACT TRUNCATED AT 250 WORDS)

Naftidrofuryl inhibits the release of 5-hydroxytryptamine and platelet-derived growth factor from human platelets

Angioplasty and bypass-grafting are associated with restenosis which limits their efficacy. Platelet-rich thrombus formation is the predominant cause of acute occlusion whereas platelet release products with proliferating properties, e.g. 5-hydroxytryptamine (5-HT) and platelet-derived growth factor (PDGF), may contribute to late restenosis. Naftidrofuryl (NAF), a drug for the treatment of peripheral vascular disease, was shown previously to inhibit platelet shape change and aggregation. This study establishes whether NAF inhibits the release of 5-HT and PDGF from platelets obtained from healthy subjects. Platelets stimulated with agonists aggregated less and released less 5-HT/PDGF when pre-incubated with NAF. Indomethacin (INDO), a cyclooxygenase inhibitor, alone inhibited aggregation and PDGF/5-HT release; NAF enhanced the inhibitory effects of INDO. The effect of NAF, on its own or in combination with a cyclooxygenase inhibitor, may therefore confer protection against graft occlusion.

Effects of naftidrofuryl oxalate, a 5-HT2 antagonist, on neurotransmission and transduction systems in the gerbil hippocampus

We investigated the effects of age and nafidrofuryl oxalate (Naftidrofuryl), a 5-HT2 antagonist, on neurotransmission and transduction systems in the gerbil hippocampus using quantitative autoradiography. [3H]Quinuclidinyl benzilate (QNB), [3H]cyclohexyl-adenosine (CHA), [3H]MK-801, and [3H]muscimol were used to label muscarinic acetylcholine, adenosine A1, N-methyl-D-aspartate (NMDA), and gamma-aminobutyric acid-A (GABAA) receptors, respectively. [3H]PN200-110 labeled L-type Ca2+ channels. [3H]Forskolin, [3H]cyclic adenosine monophosphate (cAMP), [3H]phorbol 12,13-dibutyrate (PDBu), and [3H]inositol 1,4,5-triphosphate (IP3) were used to label adenylate cyclase, cAMP-dependent protein kinase, protein kinase C (PKC), and IP3 receptors, respectively. Approximately 20% reductions in [3H]QNB, [3H]forskolin, and [3H]PDBu binding were observed in the hippocampus of 9-month-old gerbils in comparison with 5-week-old gerbils. Treatment with Naftidrofuryl (10 mg/kg, i.p., once a day for 7 days) ameliorated these reductions. No changes were found in [3H]CHA, [3H]MK-801, [3H]muscimol, [3H]PN200-110, [3H]cAMP, and [3H]IP3 binding. The results suggest that Naftidrofuryl may have beneficial effects on the age-related alterations in signal transmission and transduction systems in the brain. Because the acetylcholine system, adenylate cyclase, and PKC are considered to be involved in learning and memory processes, the result may have clinical implications.

Effects of naftidrofuryl oxalate on microsphere-induced changes in acetylcholine and amino acid content of rat brain regions

Effects of naftidrofuryl oxalate (naftidrofuryl) on neurotransmitter, acetylcholine, and amino acid content of brain regions following microsphere-induced cerebral embolism were examined to elucidate its possible therapeutic effects on ischemic brain. Rats received 900 microspheres (48 microns in diameter) via the right internal carotid artery, followed by ligation of the right common carotid artery; and histological and biochemical alterations were examined on the 3rd, 5th, and 28th days after embolism. The embolism induced increases in triphenyltetrazolium chloride- (TTC)-unstained areas and decreases in acetylcholine, glutamate, aspartate, and gamma-aminobutyric acid (GABA) contents in the cerebral cortex, striatum, and hippocampus of the right hemisphere, suggesting that microsphere embolism causes severe damage to these brain regions. Hematoxylin-eosin staining of the right cortical sections after embolism showed degeneration and necrosis of nerve cells with chromatolytic nuclei and eosinophilic cytoplasm. Changes in neurotransmitters of the left hemisphere were relatively small. Treatment with naftidrofuryl of the embolized rats with stroke-like symptoms took place from postoperative day 1 to 28. Treatment resulted in a reduction in TTC-unstained areas, less morphological damage to cerebral cortex on the 3rd and 5th days, and an appreciable restoration of acetylcholine content of three brain regions of the right hemisphere throughout the experiment, but restoration of neurotransmitter amino acids was observed to a smaller degree. The results suggest that naftidrofuryl is capable of preventing the development of ischemia-induced, sustained damage to brain regions vulnerable to oxygen deficiency, particularly by improving impaired acetylcholine metabolism.

[Action of naftidrofuryl in cerebral neovascularization after cortical lesion in rats]

In this study, naftidrofuryl's action on vascular network regeneration is evaluated after cortical lesion produced by suction. The vascular reaction was analyzed in the region of the damaged cortex and the corresponding contralateral cortex. Comparison of results by variance analysis confirms that the effect of treatment is highly significant (p = 0.008). The results thus obtained show that post-lesion angiogenesis is facilitated and that capacities of post-lesion cerebral function regeneration could also be improved.

Effects of naftidrofuryl oxalate on microsphere embolism-induced decrease in regional blood flow of rat brain

1. The purpose of the present study was to determine whether naftidrofuryl oxalate (naftidrofuryl), a vasodilator, is capable of improving brain regional blood flow of animals in sustained ischaemia. 2. Cerebral ischaemia was induced by injecting 900 microspheres (48 microns in diameter) into the right internal carotid artery of rats. Cerebral blood flow of brain regions was measured by a hydrogen clearance method on the 3rd, 7th and 28th days after the onset of ischaemia. Ischaemic animals were treated with naftidrofuryl, 15 mg kg-1 day-1 i.p., from the first to 28th day. 3. Microsphere-embolism caused a sustained decrease in cortical and striatal blood flow over a period of 28 days, whereas hippocampal blood flow was decreased on the 3rd day but not on the 7th or 28th day. On the 3rd day, the striatal and hippocampal but not cortical blood flow of naftidrofuryl-treated, microsphere-embolized rats was higher than untreated rats. On the 7th and 28th days, the cortical and striatal blood flow of the treated and untreated animals did not differ. 4. Brain slices from microsphere-embolized rats contained areas, which were not stained with triphenyltetrazolium chloride (TTC), to a similar degree on the 3rd, 7th and 28th days, indicating the genesis of cerebral infarction. TTC-unstained areas of microsphere-embolized rats that had received naftidrofuryl treatment were smaller than those of untreated rats on the 3rd and 7th days, but not on the 28th day. 5. The results suggest that naftidrofuryl improves cerebral circulation impaired by microsphere-induced ischaemia and this higher level of cerebral blood flow of the treated animal may account for the delayed development of cerebral infarction.

Naftidrofuryl, a putative activator of neuron survival, stimulates the expression of neurofilament heavy subunit in cultivated spinal cord neurons from chicken

The effect of naftidrofuryl, a drug used in ischemia for its vasodilator properties and its protective effect on neuronal survival, was investigated on the maturation of cultured chicken spinal cord neurons, focusing on the presence of proteins specific for the developing neuronal cytoskeleton. Although no influence of naftidrofuryl on the rate of growth of neurites was observed, the drug enhanced the relative amount of the high molecular weight neurofilament subunit without affecting the concentration of a microtubule-associated protein, MAP2. These findings suggest that the effect of naftidrofuryl on cultured spinal cord neurons might involve molecular events directly associated with the induction of a mature cytoskeleton architecture, instead of stimulating undifferentiated neurite growth.

[Increased viability of skin flaps using naftidrofuryl. An experimental study in the Wistar rat]

The effect of a vasodilator (naftidrofuryl) was evaluated in an experimental study in rats concerning the viability of a skin flap. The reference flap is a dorsal skin flap deliberately shaped very long in order to obtain necrosis of its distal extremity. This necrosis is measurable and sufficiently reproducible. Using a comparative study between a control group of ten rats and a group of rats treated by intraperitoneal injections of naftidrofuryl for ten days, the authors demonstrated a significant difference between necrosis in the two groups. Naftidrofuryl treatment increases the length of the viable part of the skin flap in rats. This product achieves a kind of medicinal autonomy much easier than a surgical autonomy.

In vivo effect of naftidrofuryl on 5-hydroxytryptamine-mediated constriction in rat peripheral microcirculation

Naftidrofuryl is commonly used in treatment of peripheral vascular disease. Its vasodilator action has been partly explained by its inhibitory effect of 5-HT2 receptors on peripheral arteries in vitro. The purpose of this study was to test in vivo whether naftidrofuryl selectively inhibits 5-hydroxytryptamine (5-HT)-mediated constriction of large arterioles in the peripheral microcirculation. This constriction appears to be 5-HT2 receptor-mediated. Three separate protocols were used to test the effects of naftidrofuryl: chronic injection (15 mg/kg, i.p., twice daily for 5-6 days; n = 7), acute intravenous (i.v.) infusion (15 mg/kg over 30 min; n = 7), or topical application (5 x 10(-8) M, n = 6; 5 x 10(-7) M, n = 5; 5 x 10(-6) M, n = 5; 10(-5) M, n = 7). Male Sprague-Dawley rats (145-185 g body weight) were anesthetized with sodium pentobarbital (50 mg/kg) and the cremaster muscle was prepared for intravital video microscopy. Diameter response of arterioles (70-120 microns) to increasing concentrations of locally applied 5-HT (10(-8)-10(-4) M) was assessed. In rats receiving no drug treatment, 5-HT caused vasoconstriction of arterioles beginning at 10(-6) M and reaching approximately 40% constriction at 10(-4) M. These vasoactive responses were not altered by chronic daily doses or an acute infusion of naftidrofuryl. 5-HT responses obtained with and without naftidrofuryl applied directly into the cremaster-bath also had little effect on the arteriole response at each of the four concentrations tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of naftidrofuryl oxalate, a 5-HT2 antagonist, on neuronal damage and local cerebral blood flow following transient cerebral ischemia in gerbils

Effects of naftidrofuryl oxalate (naftidrofuryl), a 5-HT2 antagonist, on neuronal damage and local cerebral blood flow was examined in a gerbil model of transient forebrain ischemia. Effect of ketanserin tartrate (ketanserin), another 5-HT2 antagonist, on neuronal damage was also examined. Pretreatment with naftidrofuryl or ketanserin prevented hippocampal CA1 neuronal loss after 5 min of transient ischemia. Naftidrofuryl did not improve hippocampal blood flow during and 1 h after transient ischemia determined by [14C]iodoantipyrine autoradiography but increased blood flow in the caudate-putamen 1 h after transient ischemia. The results show that: (1) the 5-HT2 antagonists protect against hippocampal CA1 neuronal damage; and (2) the protective effect of naftidrofuryl may not be caused by a hemodynamic mechanism but by a direct inhibitory neuromodulation via 5-HT2 antagonistic action.

Experimental and clinical study of the effect of naftidrofuryl on the recovery from peripheral nerve lesions

After primary repair of lesions of nerves and vessels, patients who were administered a vasoactive drug, naftidrofuryl, postoperatively, had a better functional recovery than untreated patients. Evidence for the favourable effect of the drug on nerve regeneration was first obtained from experiments in the rat. The sciatic nerve was transected and repaired with standard microsurgical techniques. Results were evaluated by electromyography and histology. Data indicated that treated animals had better motor responses and distal latency than untreated rats. Fibre counts showed a greater number of nerve fibres in the distal stump of treated animals. The clinical study was undertaken in cases of carpal tunnel syndrome with muscle atrophy. Assessment was performed by electrophysiology: motor and sensory conduction was studied. Data showed that all treated patients recovered totally or partially from the thenar atrophy they presented before operation, whereas thenar atrophy persisted in 37% of the patients receiving placebo. In conclusion, naftidrofuryl has an experimentally and clinically favourable effect on nerve regeneration and on muscle trophicity, but the mechanism of action of this drug is not known.

Electrophysiological evaluation of the effects of naftidrofuryl on skeletal muscle reinnervation in the rat

The effects of naftidrofuryl on the reinnervation of the rat gastrocnemius muscle after its denervation by localized freezing of the sciatic nerve were tested with electrophysiological techniques. Daily intraperitoneal injections of 30 mg/kg of naftidrofuryl do not increase the rate of axonal regeneration since early signs of reinnervation appeared as in controls around the 10th day after surgery. However, axonal sprouting is markedly increased since the percentage of muscle fibers with polyneuronal innervations was almost twice as high as in controls at the 15 and 21 day postoperative stages. The promoting effects of naftidrofuryl on polyneuronal innervation which gives rise to a redundant innervation during the first period of reinnervation constitutes an improvement of motor function which might be efficient for treatment of nerve injury and neuropathies.

Effects of naftidrofuryl on hypoxia-induced activation and mortality of human endothelial cells

The present study was designed to elucidate the possible beneficial effects of naftidrofuryl on ischemia-induced endothelium damage. For this purpose, an in vitro model was developed wherein human endothelial cells isolated from umbilical vein were submitted to hypoxia. Long-term hypoxia incubation (6 h) induced cell mortality, and naftidrofuryl strongly protected endothelial cells against this mortality in a dose-dependent manner and at concentrations as low as 10(-9) M. 66% protection was still observed after 16 h of hypoxia. Naftidrofuryl had to be present during the hypoxia incubation to exert its action; preincubation up to 24 h in the presence of naftidrofuryl could not protect endothelial cells incubated under hypoxia without naftidrofuryl. Short-term hypoxia, which does not induce mortality, strongly activates the endothelial cells with an increase in the cytosolic calcium concentration, in the phospholipase A2 activity, and in the synthesis of prostaglandin and of platelet-activating factor. It also enhances the adherence of polymorphonuclear neutrophils. Naftidrofuryl was able to markedly inhibit this whole cascade of events in a dose-dependent manner. We also demonstrated that naftidrofuryl could block the decrease in ATP concentration that results from the hypoxic conditions. These results indicate that by preserving the energetic level of the cells, naftidrofuryl prevents the activation of endothelial cells and the cell mortality induced by hypoxia. By maintaining an intact endothelium in vivo during ischemia, naftidrofuryl could prevent the further damage induced by leukocyte recruitment and activation.

Effect of naftidrofuryl and aspirin on platelet aggregation in peripheral vascular disease

Platelet aggregation in whole blood (WB) was assessed in healthy subjects and in patients with peripheral vascular disease (PVD) using a WB-free platelet counting (WB-FPC) method. Aggregation induced by stirring and platelet agonists was significantly enhanced in PVD patients. WB-FPC aggregation induced by 5-HT was diminished significantly by incubation with naftidrofuryl (NAF) in WB of PVD patients. In contrast, aspirin (acetylsalicylic acid; ASA), added in vitro, did not significantly affect 5-HT or stirring-induced WB-PFC aggregation in PVD patients. Furthermore, 5-HT-induced WB-FPC was inhibited by NAF in blood collected from PVD patients that were taking low dose aspirin. These findings suggest that NAF may be of benefit to patients with hyperaggregable platelets and elevated plasma 5-HT concentrations, factors thought to predispose to thrombotic complications.

Effects of naftidrofuryl on isolated perfused kidneys of spontaneously hypertensive rats

1. Experiments were designed to determine the effects of low concentrations (5-500 nmol/L) of naftidrofuryl, a 5-hydroxytryptamine (5-HT) antagonist, on renal functions and prostanoid synthesis responses to noradrenaline (NA) and 5-HT. Isolated kidneys of 8 week old male spontaneously hypertensive rats were perfused at a constant flow rate in a single-pass system. 2. In baseline conditions, naftidrofuryl did not modify the renal vascular resistance and the glomerular filtration rate (GFR), although it elicited a significant but not dose-dependent increase in the venous excretion of 6-keto-prostaglandin (PG) F1 alpha and thromboxane (Tx)B2, the stable end-products of PGI2 and TxA2, respectively. 3. NA increased renal vascular resistance and GFR in a dose-dependent manner and enhanced the venous excretion of 6-keto-PGF1 alpha and TxB2. Naftidrofuryl significantly attenuated the effects of NA on renal vascular resistance, abolished those on GFR and enhanced, at the highest concentration (500 nmol/L) only, those on 6-keto-PGF1 alpha excretion. 4. 5-HT increased renal vascular resistance but not GFR. It did not change the sodium excretion and the release of 6-keto-PGF1 alpha and TxB2. Naftidrofuryl blunted the RVR response to 5-HT without change in the prostanoid release. The inhibitory action of naftidrofuryl was not modified by indomethacin which, by itself, prevented the vasoconstrictor response to 5-HT.(ABSTRACT TRUNCATED AT 250 WORDS)

Naftidrofuryl affects neurite regeneration by injured adult auditory neurons

Afferent auditory neurons are essential for the transmission of auditory information from Corti's organ to the central auditory pathway. Auditory neurons are very sensitive to acute insult and have a limited ability to regenerate injured neuronal processes. Therefore, these neurons appear to be a limiting factor in restoration of hearing function following an injury to the peripheral auditory receptor. In a previous study nerve growth factor (NGF) was shown to stimulate neurite repair but not survival of injured auditory neurons. In this study, we have demonstrated a neuritogenesis promoting effect of naftidrofuryl in an vitro model for injury to adult auditory neurons, i.e. dissociated cell cultures of adult rat spiral ganglia. Conversely, naftidrofuryl did not have any demonstrable survival promoting effect on these in vitro preparations of injured auditory neurons. The potential uses of this drug as a therapeutic agent in acute diseases of the inner ear are discussed in the light of these observations.

Effects of naftidrofuryl oxalate on microsphere embolism-induced changes in tricarboxylic acid cycle intermediates of rats

The present study was undertaken to determine whether naftidrofuryl oxalate, a cerebral vasodilator, may improve or attenuate microsphere embolism-induced damage to the mitochondrial tricarboxylic acid cycle. For this purpose, the intermediates in the tricarboxylic acid cycle were determined using cerebral cortex isolated from microsphere-injected rats with and without naftidrofuryl oxalate treatment. Seven-hundred microspheres, with a diameter of 48 microns were injected into the right hemisphere through the right common carotid artery. The presence of cerebral infarction on the 3rd day after the operation was confirmed by the development of triphenyltetrazolium chloride-unstained areas in brain sections. Succinate, fumarate, malate, citrate and alpha-ketoglutarate, but not oxaloacetate, contents were significantly decreased in the right hemisphere of rats on the 3rd day following microsphere embolism. In the left hemisphere, a similar but smaller decrease in these intermediates was seen. The rats, which showed typical stroke-like symptoms, were treated with 15 mg/kg naftidrofuryl oxalate i.p., twice daily for 2.5 days, resulting in a significant reversal of the intermediate content of both hemispheres toward the control and an increased in the triphenyltetrazolium-stained area of a coronal section of the right hemisphere relative to the untreated animals. The results suggest that naftidrofuryl oxalate attenuates the development of microsphere embolism-induced cerebral infarction and improves microsphere-induced impairment of the mitochondrial tricarboxylic acid cycle. The observed effects provided evidence for a possible site of action of the agent on ischemic brain energy metabolism.

Effect of naftidrofuryl on platelet-induced vasospasm in vitro. Role of antiserotonergic actions

This study was designed to analyse the spasmolytic actions of naftidrofuryl (Dusodril, CAS 31329-57-4) more in detail, using isolated vessel segments of bovine coronary arteries (BCA). In this preparation, naftidrofuryl caused a dose-dependent inhibition of 5-HT, U 46.619 ((5Z, 9a, 11a, 13E, 15S)-11,9-(epoxymethano) prosta-5,13-dienoic acid), PGF2 alpha and KCl-induced contractions. Additionally, the actions of naftidrofuryl on platelet-induced vasospasm were investigated using arachidonic acid (AA)-stimulated platelets and BCA. Naftidrofuryl antagonized the vasocontractile effects of secreted 5-HT, but was only slightly active in reducing the TXA2-dependent vessel contraction. The suppression of ADP-induced platelet aggregation and secretion required more than 300 mumol/l naftidrofuryl. These data support the concept of a spasmolytic activity of naftidrofuryl which also involves the antagonism of platelet-derived vasocontractile mediators.

Oral naftidrofuryl prevents platelet hyperreactivity ex vivo and inhibits functional desensitization to prostacyclin in hypercholesterolemic rabbits

Among other mediators, platelet-derived serotonin (5-HT) may contribute to thromboembolic complications of atherosclerosis. We determined whether long-term oral treatment with the 5-HT2 antagonist naftidrofuryl (NAF, 50 mg/kg daily for 12 weeks) alters platelet function in cholesterol-fed (1%) rabbits. Hypercholesterolemia resulted in marked platelet hyperreactivity to collagen and ADP. This included increased aggregation, ATP secretion, and thromboxane formation; e.g., collagen-induced (1.2 micrograms/ml) platelet aggregation was stimulated to 210 +/- 10 mm/30 s in cholesterol-fed rabbits as compared with 108 +/- 9 mm/30 s in rabbits fed a standard diet (p < 0.05). Inhibition of ADP-stimulated platelet activation by the prostacyclin mimetic iloprost was significantly reduced. NAF did not reduce plasma cholesterol in hypercholesterolemia, but prevented enhanced platelet aggregation, thromboxane formation, and ATP secretion. NAF treatment significantly reduced collagen-induced (1.2 micrograms/ml) aggregation to 81 +/- 20 mm/30 s in these animals (p < 0.05). NAF also inhibited functional desensitization of platelets to iloprost, but did not alter the impaired binding of [3H]iloprost to platelet membranes in hypercholesterolemic animals. NAF also did not change any of these parameters in normocholesterolemic rabbits. These data suggest beneficial effects of NAF on platelet hyperreactivity in experimental hypercholesterolemia which may also be relevant for its clinical use.

Effect of naftidrofuryl oxalate on 5-HT2 receptors in mouse brain: evaluation based on quantitative autoradiography and head-twitch response

The effects of naftidrofuryl oxalate (LS-121) on 5-HT2 receptors in the brain were assessed in mice on the basis of quantitative autoradiography and head-twitch responses. LS-121 inhibited [3H]ketanserin (2 nM) binding in all brain areas assayed in which there were 5-HT2 receptors, such as the frontal cortex, cingulate cortex, parietal cortex, occipital cortex, temporal cortex, nucleus accumbens, caudate-putamen, olfactory tubercle and hippocampus. In the frontal cortex, which has the highest density of 5-HT2 receptors, the Ki value of LS-121 was 6.08 x 10(-8) M. The inhibitory potencies of methysergide and ritanserin for 5-HT2 receptors were about 16- and 60-fold stronger, respectively, than that of LS-121. Moreover, in behavioral studies, LS-121 (12.5-50 mg/kg i.p.) produced dose-dependent and significant inhibitory effects on head twitches induced by 5-hydroxytryptophan (5-HTP) plus pargyline, which is a 5-HT2 receptor-dependent behavior in mice. These results suggest that LS-121 inhibits 5-HTP plus pargyline-induced head twitches by blocking 5-HT2 receptors.

Serotonin-induced contractility in human saphenous vein is inhibited by naftidrofuryl

Vascular endothelial denudation contributes to vasospasm by causing platelet aggregation and the subsequent release of vasoconstrictors such as serotonin. It has recently been suggested that naftidrofuryl fumarate (NFT) may oppose serotonin-induced vasoconstriction. Fourteen rings of human saphenous vein from 14 patients undergoing varicose vein surgery were tested in standard organ bath experiments. Cumulative dose-response curves and maximal contraction in response to serotonin were recorded and this was repeated in the presence of NFT at 10(-6) and 10(-3) mol/l. The difference in maximal contractility between the three sets of curves was significant (P < 0.0001). Sensitivity to serotonin in each of the three curves was measured using the concentration for half-maximal response; differences were again significant (P < 0.0001). It is concluded that NFT reduces serotonin-induced contractility in a dose-dependent fashion in rings of human saphenous vein in vitro. These results suggest a possible role for NFT in reducing vasospasm and support further investigation of this drug.

Beneficial effects of naftidrofuryl oxalate on brain regional energy metabolism after microsphere-induced cerebral embolism

The present study was undertaken to elucidate the possible therapeutic effects of naftidrofuryl on energy metabolism of brain regions impaired for extended periods by microsphere embolism. Nine hundred microspheres (48 microns in diameter) were injected into the right internal carotid artery of rats, and changes in their behavior and energy metabolism of the cortex, striatum and hippocampus of both hemispheres were determined with and without naftidrofuryl treatment. Microsphere embolism induced increases in lactate, glucose and glycogen contents and decreases in ATP and creatine phosphate of these brain regions of the right hemisphere for up to 28 days after the operation, suggesting long-lasting cerebral ischemia or sustained damage to energy metabolism. These changes were gradually reversed with time after the operation. Microsphere-injected rats were treated twice a day with 15 mg/kg naftidrofuryl, and their behavioral and metabolic protection were determined on the 3rd, 5th and 28th days after the operation. Treatment of embolized animals with naftidrofuryl improved these variables appreciably on the 3rd and 28th days, but little on the 5th day. The improvement on the 3rd day was more evident in all brain regions monitored than that on the 28th day. The results suggest that naftidrofuryl exerts beneficial effects on the energy metabolism of brains damaged by microsphere embolism, the mechanism of which may be due to protection against the development of embolism-induced derangement.

A comparative study on the effect of various pharmacological agents on the survival of skin flaps in the rat

The effects of chlorpromazine, pentoxifylline, terbutaline, allopurinol, phenoxybenzamine, naftidrofuryl, hydralazine and trimetazidine were investigated on caudally based dorsal flaps. The study was performed on 108 rats, divided in 9 groups of 12 animals each, one of which served as a control group. All treated groups showed a significantly greater survival of the flap than the control group. Comparisons among different groups showed better outcome in those receiving trimetazidine and hydralazine, followed by those receiving naftidrofuryl and phenoxybenzamine.

Involvement of serotonergic neuronal systems in the anti-amnesic action of naftidrofuryl oxalate

The effects of naftidrofuryl oxalate on cycloheximide- and 5-hydroxytryptophan (5-HTP)-induced amnesia were investigated using a passive avoidance task in mice. Naftidrofuryl oxalate significantly improved the cycloheximide-induced amnesia. This effect of naftidrofuryl oxalate was antagonized by 5-HTP, a serotonin (5-HT) precursor, and by p-chloroamphetamine (PCA), a 5-HT releaser. Single administration of 5-HTP in combination with pargyline, a monoamine oxidase inhibitor, induced amnesia (5-HTP-induced amnesia). This amnesia was attenuated by ritanserin, a 5-HT2-selective antagonist, but not by pindolol, a 5-HT1-selective antagonist. Naftidrofuryl oxalate also attenuated the 5-HTP-induced amnesia. A binding study revealed that naftidrofuryl oxalate inhibited the binding of [3H]ketanserin to 5-HT2 receptors in mouse brain synaptic membrane in a dose-dependent fashion (IC50 = 1.42 x 10(-7) M), but did not inhibit that of [3H]serotonin to 5-HT1 receptors. These results suggest that naftidrofuryl oxalate may attenuate cycloheximide- and 5-HTP-induced amnesia by blocking 5-HT2 receptor subtypes.