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Scopolamine and physostigmine do not alter visual detection of change: relationships to a model of lateral geniculate operations.

The effects of physostigmine and scopolamine were tested on 5 male subjects using a task based on a model of cross-inhibition among lateral geniculate neurons. The task consisted of detecting and locating a change (appearance or disappearance) of one point of light in an array of points. Earlier research suggested that the task was sensitive to drugs and pathology. In the present study, neither drug showed significant effects on any of three task variables used, although differences between subjects were significant. These findings show that the task is sensitive to individual differences but insensitive to changes in cholinergic activity produced by physostigmine and scopolamine, even though such changes should affect neuronal functioning at the lateral geniculate.

Adult↗

The long-term increase of baseline and reflexly augmented levels of human vagal-cardiac nervous activity induced by scopolamine.

We tested the hypothesis that transdermal scopolamine increases vagal-cardiac nervous outflow over the long term in 16 healthy young men. Twenty-four hours after application of one scopolamine patch, the average RR interval was increased by 13% and the average standard deviation of the RR interval (taken as an index of the level of vagal-cardiac nervous activity) was increased by 31%. Baroreceptor-cardiac reflex responsiveness (as reflected by prolongation of RR interval provoked by graded neck suction) also was increased substantially. These findings suggest that vagal-cardiac nervous activity can be augmented pharmacologically in man on a long-term basis. Since vagal outflow influences cardiac electrical properties in an important way, these findings may have therapeutic implications.

Adult↗

Transdermal scopolamine in the treatment of acute vertigo.

A double-blind, parallel investigation was undertaken to evaluate the efficacy of transdermally delivered scopolamine hydrobromide in acute vertigo as compared to meclizine hydrochloride and placebo. Statistical analysis of subjective patient responses and clinical observations suggested that both scopolamine and meclizine are more effective than placebo. Both have significant, but different, side effects.

Acute Disease↗

Effects of scopolamine on interhemispheric EEG coherence in healthy subjects: analysis during rest and photic stimulation.

The present study of coherence analysis, in 16 healthy male volunteers, aged 24-31 years, showed that the administration of 0.25 mg of scopolamine significantly reduced interhemispheric coherence in the delta and beta-1 bands in the resting state. Scopolamine also caused a significant increase both in EEG coherence during PS and in PS-related coherence reactivity in the beta band. In addition, this compound significantly reduced total WMS scores. These findings suggest that, in addition to causing cognitive impairments, central cholinergic dysfunction can alter interhemispheric functional connectivity under both nonstimulus and stimulus conditions.

Adult↗

Long-term clomipramine treatment upregulates forebrain acetylcholine muscarinic receptors, and reduces behavioural sensitivity to scopolamine in mice.

We have investigated the effects of long-term treatment with clomipramine, a tricyclic antidepressant, on central muscarinic acetylcholine receptors (mAChR) in mice. Repeated clomipramine administration resulted in an increase in the forebrain receptor density value (Bmax) for [3H]quinuclidinyl benzilate, a muscarinic ligand (P < 0.05), that was dependent on dose per administration (saline or 5, 10, or 20 mg kg(-1) once a day for 7 days) and number of days treated (20 mg kg(-1) for 1, 3, 5, or 7 days). No change in apparent affinity (defined as the reciprocal of the dissociation constant) (KD) occurred. Seven daily treatments with clomipramine (saline or 5, 10, or 20 mg kg(-1)) reduced hyperlocomotion induced by scopolamine (0.5 mg kg(-1), s.c.) dose-dependently, and the effect of 20 mg kg(-1) clomipramine was significant (P < 0.05). These results suggest that an upregulation of mAChR is produced by repeated clomipramine administration, and such a change is responsible for the decreased sensitivity to the muscarinic antagonist scopolamine.

Animals↗

What can preservation of autobiographic memory after muscarinic blockade tell us about the scopolamine model of dementia?

Autobiographic memory is reported to be impaired in patients with Alzheimer's disease (AD). To determine if cholinergic blockade fully reproduces the amnestic disorder found in dementia, we evaluated aspects of autobiographic and episodic memory in six healthy elderly controls after both scopolamine and placebo administration compared with untreated age- and education-matched patients with AD. The performance of patients with AD was significantly worse than that of controls after both treatment conditions. Scopolamine impaired episodic but not autobiographic memory. Thus, even though the cholinergic system is severely affected in patients with AD, muscarinic blockade alone does not seem to be a good model of this disorder.

Aged↗

Transdermal scopolamine: an alternative to ondansetron and droperidol for the prevention of postoperative and postdischarge emetic symptoms.

BACKGROUND: Given the controversy regarding the use of droperidol and the high cost of the 5-HT3 antagonists, a cost-effective alternative for routine use as a prophylactic antiemetic would be desirable. We designed two parallel, randomized, double-blind sham and placebo-controlled studies to compare the early and late antiemetic efficacy and adverse event profile of transdermal scopolamine (TDS) 1.5 mg, to ondansetron 4 mg IV, and droperidol 1.25 mg IV for antiemetic prophylaxis as part of a multimodal regimen in "at risk" surgical populations. METHODS: A total of 150 patients undergoing major laparoscopic (n = 80) or plastic (n = 70) surgery procedures received either an active TDS patch (containing scopolamine 1.5 mg) or a similar appearing sham patch 60 min before entering the operating room. All patients received a standardized general anesthetic technique. A second study medication was administered in a 2-mL numbered syringe containing either saline (for the two active TDS groups), droperidol, 1.25 mg, or ondansetron, 4 mg (for the sham patch groups), and was administered IV near the end of the procedure. The occurrence of postoperative nausea and vomiting/retching, need for rescue antiemetics, and the complete response rates (i.e., absence of protracted nausea or repeated episodes of emesis requiring antiemetic rescue medication) was reported. In addition, complaints of visual disturbances, dry mouth, drowsiness, and restlessness were noted up to 72 h after surgery. RESULTS: There were no significant differences in any of the emetic outcomes or need for rescue antiemetics among the TDS, droperidol, and ondansetron groups in the first 72 h after surgery. The complete response rates varied from 41% to 51%, and did not significantly differ among the treatment groups. The overall incidence of dry mouth was significantly more frequent in the TDS groups than in the droperidol and ondansetron groups (21% vs 3%). CONCLUSIONS: Premedication with TDS was as effective as droperidol (1.25 mg) or ondansetron (4 mg) in preventing nausea and vomiting in the early and late postoperative periods. However, the use of a TDS patch is more likely to produce a dry mouth.

Adjuvants, Anesthesia↗

Application of ion-pair high performance liquid chromatography for analysis of hyoscyamine and scopolamine in solanaceous crude drugs.

A new ion-pair high-performance liquid chromatographic method for the analysis of hyoscyamine and scopolamine in various kinds of crude drugs derived from solanaceous plants was evaluated using sodium dodecyl sulfate as a counter ion. A reversed-phase chromatographic system consisting of a chemically bonded ODS silica gel column with phosphate buffer (pH 2.5)-acetonitrile (65:35) containing 17.5 mM sodium dodecyl sulfate as the mobile phase was used. Hyoscyamine and scopolamine in crude drugs derived from Scopolia, Atropa, Hyoscyamus and Datura species were separated from other compounds in the crude drugs and determined within 20 min after direct injection of the solution extracted with the mobile phase. The results for various kinds of samples are presented.

Atropine↗

Effects of bifemelane hydrochloride (MCI-2016) on acetylcholine level reduced by scopolamine, hypoxia and ischemia in the rats and mongolian gerbils.

Effects of bifemelane hydrochloride (MCI-2016) on acetylcholine (ACh) level in the cerebral cortex and hippocampus of rats and Mongolian gerbils were examined. In normal rats, MCI-2016 (30 mg/kg, i.p.) slightly increased ACh content in the cerebral cortex. Scopolamine (1 mg/kg, i.p.) or hypoxia (95% N2 +5% O2, 9 min) decreased ACh level and pretreatment of MCI-2016 attenuated the decrement of ACh level in the rats. ACh level in the brain of Mongolian gerbils was significantly decreased following ligation of bilateral carotid arteries. In this case, MCI-2016 also attenuated the decrement of ACh level. These results suggest that improvement by MCI-2016 of behavioral impairment observed in the animals treated with scopolamine, hypoxia or ischemia may be, at least partly, attributed to the amelioration of decreased ACh level in the brain.

Acetylcholine↗

Protective effect of eurystatins A and B, new prolyl endopeptidase inhibitors, on scopolamine-induced amnesia in rats.

Eurystatins A and B, which are produced by Streptomyces eurythermus R353-21, potently inhibited Flavobacterium prolyl endopeptidase (PED) with IC50 values of 0.004 and 0.002 micrograms/ml, respectively, while no inhibition was observed against another 5 proteases, even at 100 micrograms/ml. The protective effect of eurystatins A and B against scopolamine (3 mg/kg, i.p.)-induced amnesia in rats was evaluated by the step-through one-trial passive avoidance method. When administered i.p. 30 min prior to the acquisition trial, both eurystatins A, at 2-8 mg/kg, and B, at 4-8 mg/kg, significantly protected rats from the amnesic effect of scopolamine without behavioral side effects.

Amino Acid Sequence↗

Effect of long-term administration of berberine on scopolamine-induced amnesia in rats.

The effect of berberine (BER) on scopolamine (SCOP)-induced amnesia was investigated in a step-through passive avoidance task in rats. It was observed that BER at the doses of 0.1 and 0.5 g/kg after 7-day or 14-day administration significantly improved SCOP-induced amnesia. The anti-amnesic effect of BER after 14-day administration on the SCOP-induced amnesia was significantly augmented by physostigmine or neostigmine, and completely reversed by scopolamine N-methylbromide. These results suggest that the antiamnesic effect of BER after 14-day administration may be related to the increase in the peripheral and central cholinergic neuronal system activity.

Amnesia↗

Transdermal scopolamine as treatment of bradyarrhythmias.

Fifteen patients with different degrees of chronic bradyarrhythmias of supraventricular origin were studied with Holter monitoring before and during application of a transdermal patch of scopolamine. No changes were found in the mean or minimal heart rates, standard deviation of the RR interval, or the degree of bradyarrhythmia. It is concluded that transdermal scopolamine is not an adequate treatment of chronic symptomatic bradyarrhythmias.

Administration, Cutaneous↗

Effects of methamphetamine and scopolamine on variability of response location.

Methamphetamine and scopolamine were studied in monkeys responding under a multiple fixed-ratio fixed-interval schedule of reinforcement. A response on any one of six levers could satisfy the schedule requirements. Variability of response location was evaluated in terms of switches, where a switch was defined as a response on one lever followed by a response on a different lever. Under baseline conditions the fixed-ratio schedule generated a high rate of responding and a low level of variability, while the fixed-interval schedule generated a low rate of responding and a high level of variability. Both methamphetamine (0.1 to 0.5 mg/kg) and scopolamine (2.4 to 240 microgram/kg) decreased overall response rate and increased variability of response location in each component of the multiple schedule with increasing doses of drug. At lower doses both drugs were found to decrease rate without affecting response variability.

Animals↗

Impairment of saccadic eye movements by scopolamine treatment.

The effects of Scopolamine on the dynamics of saccadic eye movements, stimulated over a random time interval, have been investigated in humans. A 0.5-mg dose of the drug (intramuscular injection) had various influences on the basic saccadic parameters. For all subjects duration increased and peak velocity decreased, while for 50% of the subjects saccades became hypometric and latency increased. Standard deviation increased consistently too. Moreover, the Scopolamine treatment affected postsaccadic fixation; at the end of many saccades, the eye drifted considerably, but stability was recovered after a few seconds.

Adult↗

Effects of scopolamine on working memory in rats in a delayed matching-to-position task, employing a subject-centered procedure.

The effect of scopolamine hydrobromide on a delayed matching-to-position task was examined while controlling for two confounding factors, i.e., mediating behavior and slow performance on a task. The task was given on the basis of a subject-centered method in which delay intervals are dependent on subjects' performance. The performance of individual subjects, rather than averaged group performance, was taken as the focus of the analysis. The results indicated that scopolamine had an effect not only on speed of performing the task but also on the length of the retention interval. The effects differed considerably among individuals: the effects on both the length of the retention interval and the speed of performance were found for two of the five subjects. An effect on speed of performance alone was found for one subject. No effects on either measure were found in a further two subjects.

Animals↗

Effect of transdermally administered scopolamine on the vestibular system in humans.

In order to elucidate the effect of scopolamine on the vestibular system in humans, various experimentally-induced forms of nystagmus, i.e. caloric nystagmus, rotational nystagmus, optokinetic nystagmus, visual-vestibular interaction and optokinetic after nystagmus, were evaluated before and after the administration of two pieces of Scopoderm-TTS or placebo patches retro-auricularly. Scopolamine reduced the responses of both the caloric and optokinetic after nystagmus compared with the placebo. The possible action site of this drug is discussed.

Administration, Cutaneous↗

Responsiveness of life-threatening refractory emesis to gabapentin-scopolamine therapy following posterior fossa surgery. Case report.

Craniotomy-associated chronic emesis can be refractory to currently approved antiemetic therapy. The authors describe a man who suffered 4 weeks of severe refractory emesis, failure to thrive, and a 40-lb weight loss after he underwent resection of a posterior fossa cholesteatoma. The patient experienced complete resolution of emesis and anorexia in response to combined gabapentin-scopolamine therapy. This case provides anecdotal evidence for the use of gabapentin-scopolamine therapy in patients with chronic, refractory nausea and emesis, particularly following posterior fossa surgery, during which medullary nausea and emesis centers may be affected.

Amines↗

Facilitating effects of histamine on spatial memory deficit induced by scopolamine in rats.

AIM: To investigate whether or not histamine was involved in scopolamine-induced spatial memory deficits evaluated in 8-arm radial maze performance of rats. METHODS: Eight-Arm radial maze performance was used to measure spatial memory in rats, and the brain regions were subsequently dissected and histamine contents were determined by HPLC. RESULTS: Intracerebroventricular (icv) injection of histamine (100 or 200 ng) or thioperamide (50 micrograms), and intraperitoneal (i.p.) injection of histidine (1000 mg/kg) ameliorated memory impairment induced by scopolamine regarding both parameters of radial maze performance. 2-Thiazolylethylamine, but not 4-methylhistamine showed the similar effect to histamine. Both histamine (200 ng, icv) and histidine (1000 mg/kg, i.p.) were equally effective in increasing the histamine content in the cortex, hippocampus, and hypothalamus. CONCLUSION: These results suggest that brain histamine plays an important role in learning and memory, and its action may be due to cholinergic neurons.

Animals↗