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PubMed1969

The effects of iproniazid and reserpine on the accumulation of granular vesicles and noradrenaline in constricted adrenergic nerves.

1. The accumulation of granular vesicles proximal to a constriction applied to hypogastric nerves has been investigated with the electron microscope in cats treated with reserpine and/or iproniazid.2. The ultrastructural changes have been correlated with the accumulation of noradrenaline at the same site in similarly treated animals.3. The findings give further support to the view that granular vesicles constitute a major storage site for intraneuronal noradrenaline.

Animals↗
PubMed1970

The effect of reserpine treatment and decentralization on the ion distribution in the vas deferens of the guinea-pig.

1. The ion distribution in the vas deferens of the guinea-pig was determined following reserpine treatment and decentralization, procedures known to increase the sensitivity of this muscle to drug stimulation.2. There were no significant changes in the estimated intracellular ion concentrations following the two procedures. The half-times of (42)K and (36)Cl effluxes were also unaltered.3. As far as ion content is concerned there is no basis for suggesting an altered resting membrane potential in supersensitive smooth muscle.

Animals↗
PubMed1970

Acid metabolites of monoamines in avian brain; effects of probenecid and reserpine.

1. The concentration of the dopamine (DA) metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the anterior part of the nucleus basalis of pigeon brain was found to be 0.17 +/- 0.01 mug/g, which is about one-fifth of the concentration of homovanillic acid (HVA) in this region. In the chicken, the concentration of HVA in the (entire) nucleus basalis was 0.06 +/- 0.006 mug/g, lower than in any other species examined, and giving a ratio of DA to HVA of about 50. The concentration of DOPAC in the 8 day old chick was 0.053 +/- 0.002 mug/g.2. Probenecid, 200 mg/kg intramuscularly, doubled the content of DOPAC in the nucleus basalis of the pigeon and increased the concentration of HVA in both the pigeon and the chicken by a factor of 4 to 5. These findings demonstrate the existence, in avian brain, of an active transport mechanism for the removal of acidic substances and explain the low concentrations of the acids found in bird brain.3. A method is described for the estimation of 5-hydroxytryptamine (5-HT) and 5-hydroxyindolylacetic acid (5-HIAA) in the same tissue sample. Probenecid caused an increase in the 5-HIAA content but produced no change in the 5-HT content of the nucleus basalis of pigeon brain.4. Reserpine caused a fall in the content of acidic DA metabolites in the nucleus basalis of the pigeon. The effect was more pronounced after raising the concentration of these acids with probenecid.5. Treatment of pigeons with pargyline (100 mg/kg 17 hr before decapitation) did not significantly increase the DA content of the nucleus basalis, but it prevented to some extent the loss in DA caused by reserpine.6. Pigeons and chickens were sedated by probenecid. The deepest sedation occurred at about the same time as the greatest increase in the acidic amine metabolites in the brain.7. Intracisternal injection of HVA in the pigeon and intravenous injection of large amounts of HVA, DOPAC, 5-HIAA or 3,4-dimethoxyphenylacetic acid into newly hatched chicks did not produce any sedation or other effects on behaviour. In contrast, injection of sodium gamma-hydroxybutyrate caused paralysis followed by prostration and eye closure.8. Estimation of the concentration of HVA in the brain of the young chick after intravenous injection of the acid (100 mg/kg) showed that the concentration was of the same order of magnitude as it is in animals given probenecid; this suggests that the sedation which follows probenecid is not related to the accumulation of acidic amine metabolites.

Animals↗
PubMed1971

Effects of methysergide on platelets incubated with reserpine.

1. Platelets were incubated with methysergide and related compounds (2-bromo lysergic acid (BOL), ergotamine and methyl ergotamine) together with reserpine.2. Methysergide inhibited the normal aggregation response of platelets to 5-hydroxytryptamine (5HT) but did not affect the reduction in the 5HT content caused by reserpine, or the uptake of 5HT by the platelets.3. BOL, ergotamine and methyl ergotamine behaved similarly. Methysergide had greater anti5HT potency than BOL, and methyl ergotamine had greater potency than ergotamine.4. The use of platelets as a model for synaptic preparations is discussed.5. The role of 5HT receptor sites on the platelet membrane and the significance of the results for migraine patients treated with methysergide are discussed.

Blood Platelets↗
PubMed1975

Influence of cocaine and sodium on bretylium uptake by reserpine-treated guinea-pig left atrium.

1 The effects of cocaine and sodium on bretylium uptake into sympathetic nerve terminals were investigated in the reserpine-treated guinea-pig left atrium. The ability of bretylium pretreatment to increase the retention of noradrenaline was used as an index of bretylium uptake. Such increased retention has been assessed both by direct measurement and by the ability of tyramine to produce an inotropic response. 2 The restoration of the response to tyramine after incubation with noradrenaline was abolished when the atrium was pretreated with bretylium in the presence of cocaine. When bretylium was added before cocaine, or when alpha-methyl-noradrenaline (not a substrate for monoamine oxidase) was used for incubation, the responses to tyramine were restored in the normal way. 3 Bretylium greatly enhanced the retention of [3-H]-noradrenaline; when bretylium was added in the presence of cocaine, [3-H]-noradrenaline retention was severely impaired. 4 Pretreatment with bretylium in a low-sodium (25 mM) or sodium-free medium significantly decreased the retention of [3-H]-noradrenaline, as compared with the control. 5 Potassium deprivation did not modify the enhanced retention of [3-H]-noradrenaline induced by bretylium pretreatment. 6 Bretylium was released from the nerve terminals by exposure of the preparation to a sodium-free medium or to a solution containing calcium 50 mM, leading to a considerable decrease in [3-H]-noradrenaline retention. 7 The results are consistent with the view that both cocaine and sodium deprivation block the uptake of bretylium by the adrenergic nerve terminals, and that bretylium is probably taken up by a mechanism similar to or identical with the uptake system for noradrenaline and other amines.

Animals↗
PubMed1981

Thermic and tremorogenic effects of thyroliberin (TRH) in reserpine-treated mice--the non-involvement of GABA-ergic mechanisms.

Administration of thyroliberin (TRH) to reserpinized mice causes tremor and counteracts the hypothermia in a dose-dependent fashion. The thyroliberin response is inhibited by gamma-hydroxybutyric acid (GHB) and baclofen, but not by other, more specific GABA-ergic agents, such as THIP, gamma-acetylenic GABA, and sodium valproate. Picrotoxin neither potentiates nor inhibits the thyroliberin actions. Nor are the thyroliberin effects dependent on cholinergic, monoaminergic or histaminergic mechanisms. The results repudiate a current hypothesis, that the peptide actions may be mediated by GABA-ergic pathways in the brain.

Animals↗
PubMed1980

The effects of reserpine on motor activity and pallidal discharge in monkeys: implications for the genesis of akinesia.

1. A reversible disturbance of basal ganglia function was produced in monkeys by the intramuscular administration of reserpine.2. Pallidal discharge was then compared with that recorded in the same animals during movement performance and following passive manipulation of the limbs.3. Akinesia, loss of postural support of the trunk, head and neck and absent postural reflexes were the predominant motor abnormalities produced by reserpine administration.4. Occasionally, postural tremor and catatonia were apparent. Rigidity and resting tremor were absent.5. Recordings made in the pallidum during the presence of akinesia revealed a marked reduction in natural neuronal discharge.6. Some pallidal neurones that remained active were driven in an uncharacteristic manner by peripherally generated afferent inputs from wide territories and by a variety of peripheral stimuli.7. The findings suggest the hypothesis that the akinesia in these animals was due to the diminished pallidal activity, and that pallidal discharge is normally a prerequisite for the performance of spontaneous motor activity. Pallidal neuronal firing may provide a background excitability to motor regions involved in the maintenance and elaboration of natural motor activity.

Action Potentials↗
PubMed1958

Effect of reserpine pretreatment on stimulation of the accelerans nerve of the dog.

Pretreatment with two doses of reserpine (each 0.1 mg/kg, intraperitoneally) sensitizes the heart to the positive chronotropic action of norepinephrine and reduces the response to stimulation of the accelerans nerve. Ganglionic transmission remains unaffected. The results indicate that the presence of certain stores of peripheral sympathetic transmitter is essential for the production of tachycardia by stimulation of the accelerans nerve.

Animals↗
PubMed1965

Tritium: distribution in Busycon canaliculatum (L.) injected with labeled reserpine.

Tritiated reserpine was injected into the body cavities of specimens of Busycon canaliculatum (Mollusca, Gastropoda). Only the ganglia, liver, and kidney were radioactive throughout the 14-day experiment. Radioactivity of the kidney and liver increased after the first measurement; that of the ganglia declined during the first day but later remained constant.

Animals↗
PubMed1999

Inhibition of the emergence of ciprofloxacin resistance in Streptococcus pneumoniae by the multidrug efflux inhibitor reserpine.

Recent evidence supports the contribution of a multidrug efflux mechanism to fluoroquinolone resistance in Streptococcus pneumoniae. In this paper I show that reserpine, an inhibitor of multidrug transporters in gram-positive bacteria, dramatically suppresses the in vitro emergence of ciprofloxacin-resistant variants of S. pneumoniae, suggesting that the combination of a fluoroquinolone with an inhibitor of multidrug transport may help preserve the efficacy of this class of antibiotics.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1980

Cutaneous microcirculation in systemic sclerosis and response to intra-arterial reserpine.

The cutaneous microcirculation in the hand was measured in 23 patients with systemic sclerosis, 19 with Raynaud's phenomenon and four without Raynaud's phenomenon, and 20 controls. The patients with Raynaud's phenomenon had a reduced basal blood flow and an exaggerated further reduction on local cold stimulation, though both were normal in patients without Raynaud's phenomenon. Reflex-induced vascular changes by cold stimulation of the contralateral hand showed no differences between the three groups. The blood flows were similar in the affected skin of the anterior chest wall in four patients with systemic sclerosis and peripheral Raynaud's phenomenon and matched controls. In the seven most severely affected patients 1 mg of intra-arterial reserpine produced a prompt improvement in the cutaneous microcirculation which usually lasted one to three weeks but occasionally much longer. By judicious use of repeated injection guided by measurements of the microcirculation it was possible to heal indolent ulcers of the fingers. The results indicate that vascular changes are common in systemic sclerosis but are not fundamental in the pathogenesis of the disease. More probably there is a general soft tissue abnormality that usually but not necessarily affects the vessels.

Cold Temperature↗
PubMed1974

Effects of reserpine and chlorpromazine on 5-hydroxytryptamine uptake of platelets from migrainous and control subjects.

Platelet aggregation experiments confirm differences between the 5-hydroxytryptamine (5-HT) receptors of migrainous and control platelets. However, no differences have been found in 5-HT uptake, in the presence of reserpine or chlorpromazine, into migrainous and control platelets. The results support the hypothesis that receptors for 5-HT induced platelet aggregation provide a model for vascular receptors causing constriction and are distinct from those transferring 5-HT through the platelet membrane.

Blood Platelets↗
PubMed1975

The effect of cocaine, reserpine, and 6-hydroxydopamine on the response of the perfused central artery of the rabbit ear to sympathomimetic amines.

The perfused central artery of the rabbit ear was less sensitive to extraluminal than to intraluminal noradrenaline, but the reverse was true for metaraminol, methoxamine, metanephrine, and isoproterenol. No difference was noted between the extraluminal and intraluminal potency of phenylephrine. Cocaine potentiated the effect of extraluminal and intraluminal noradrenaline, but decreased that of intraluminal phenylephrine. Irrespective of the route of administration, the constrictor potencies of the sympathomimetic amines were not affected by cocaine. Arteries of reserpine-treated rabbits were supersensitive to extraluminally and intraluminally applied noradrenaline and phenylephrine, but they were not supersensitive to metaraminol. 6-Hydroxydopamine effectively destroyed adrenergic nerve endings of the central ear artery and increased its responses to both extraluminal and intraluminal noradrenaline and phenylephrine. However, only the constrictor potencies of intraluminally applied metaraminol and methoxamine were enhanced by 6-hydroxydopamine. The apparent discrepancies between the results obtained by various procedures that eliminate or impair the nerve uptake process suggest that the difference in the constrictor potency of extraluminal and intraluminal sympathomimetic amines is probably unrelated to their uptake by nerves located in the adventitio-medial junction of the artery.

Animals↗
PubMed1982

The effects of some antipsychotic drugs, D-amphetamine, and reserpine on the concentration and rate of accumulation of tryptamine and 5-hydroxytryptamine in the mouse striatum.

The mouse striatum contains about 2 ng/g of tryptamine and 600 ng/g of 5-hydroxytryptamine. No significant changes in mouse striatal tryptamine were observed after the administration of chlorpromazine, haloperidol, spiperone, or alpha-flupenthixol. The levels of 5-hydroxytryptamine were moderately reduced by chlorpromazine, spiperone, and alpha-flupenthixol but not by haloperidol. The administration of antipsychotic drugs to mice pretreated with a monoamine oxidase inhibitor (pargyline) produced an increase in the rate of accumulation of striatal tryptamine compared with that of pargyline-treated mice. In contrast, the rate of accumulation of 5-hydroxytryptamine after monoamine oxidase inhibition was reduced by chlorpromazine, spiperone, and alpha-flupenthixol but not haloperidol. D-Amphetamine administration did not change either tryptamine or its 5-hydroxyderivative while reserpine increased tryptamine and reduced 5-hydroxytryptamine. The results suggest that changes in striatal tryptamine may be controlled by the availability of tryptophan, the amino acid precursor of tryptamine.

Animals↗
PubMed1981

Lack of effect of morphine, reserpine, and halothane on oscillation of plasma insulin in M. mulatta.

Oscillating plasma insulin levels, with periods averaging 9 min, in fasting rhesus monkeys have been previously reported by us. To test whether an oscillator in the central nervous system might be driving these oscillations, we subjected five male rhesus monkeys to morphine, reserpine, and halothane, agents known to affect the central nervous system, in an attempt to either disrupt or change the frequency of the oscillations. We could demonstrate no significant effect of any of the three drugs on the oscillations. We conclude, therefore, that the oscillations in plasma insulin are not driven by an oscillator in the central nervous system. Coupled with the results of others, these data suggest that these oscillations are probably due to an intrinsic pancreatic pacemaker.

Animals↗