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At least 811 records · Page 45Linked to original sources
PubMed1981

Differential reversal by scopolamine and THIP of the antistereotypic and cataleptic effects of neuroleptics.

Scopolamine reversed the neuroleptic-induced catalepsy and neuroleptic blockade of amphetamine-induced stereotypies in rats. The effect on catalepsy was the most pronounced. Butyrophenones were mainly sensitive to scopolamine reversal whereas the thioxanthenes cis-Z-flupentixol and piflutixol were not significantly influenced. THIP did not change the effects of cis-Z-flupentixol, fluphenazine and haloperidol. The relevance of these findings for the use of stereotypy and catalepsy tests as screening for antiscizophrenic and extrapyramidal side-effects, respectively, is discussed.

Amphetamine↗
PubMed1988

Scopolamine modulates apomorphine-induced behavior in rats treated with haloperidol or SCH 23390.

In acute experiments, scopolamine (1.0 mg/kg) potentiated apomorphine stereotypy and inhibited the antistereotypic effect of both haloperidol (0.5 mg/kg) and SCH 23390 (0.2 mg/kg). Daily administration of either haloperidol (0.5 mg/kg) or SCH 23390 (0.2 mg/kg) for 3 weeks produced enhanced stereotypic responses to apomorphine. Co-administration of scopolamine (1.0 mg/kg) with haloperidol or SCH 23390 significantly reduced the behavioral supersensitivity produced by haloperidol or SCH 23390 alone. It is suggested that both D-1 and D-2 dopamine receptors are linked to a cholinergic mechanism.

Animals↗
PubMed1989

Effect of S-adenosyl-L-methionine on impairment of working memory induced in rats by cerebral ischemia and scopolamine.

A repeated acquisition procedure in a 3-panel runway apparatus was used to investigate the effects to S-adenosyl-L-methionine (SAM) on impairment of working memory produced either by cerebral ischemia or by scopolamine in rats. Cerebral ischemia (2-10 min) produced duration-dependent increases in the number of errors (pushes made on the two incorrect panels located at each choice point) and increased latency (time before the rat reached the goal box). The increase in errors induced by a 5 or 10 min period of ischemia decreased gradually in subsequent training sessions, returning to the control levels in 6 days. The increases in both errors and latency induced by 5 min of ischemia were significantly reduced by 100 and 180 mg/kg SAM administered i.p. immediately after blood recirculation and 1 h before a test conducted 24 h after ischemia. SAM at doses up to 180 mg/kg nevertheless failed to reduce the increases in errors and latency if they were induced by 0.56 mg/kg of scopolamine. These results suggest that SAM has a beneficial effect on memory that has been impaired by cerebral ischemia.

Animals↗
PubMed1991

Midlatency auditory-evoked responses: effect of scopolamine in the cat and implications for brain stem cholinergic mechanisms.

The objective of this study has been to define the role of cholinergic mechanisms in the generation of "wave A," a middle latency auditory-evoked potential recorded as a positivity with a 20-25 ms peak latency from the vertex of conscious cats. Wave A and its generator system have particular significance as an experimental model of the human middle latency component "P1." Both the feline wave A and the human P1 are characterized by a long recovery cycle, disappearance during slow wave sleep, and reappearance during rapid eye movement (REM) sleep and during wakefulness. The orchestration of several phenomena of REM sleep are known to involve muscarinic cholinergic mechanisms in the brain stem. Therefore, middle latency auditory-evoked potentials were studied in awake cats before and after injection of a cholinergic antagonist, scopolamine. Wave A and the successive negative potential were abolished by scopolamine in a dose-dependent fashion. This effect occurred within 5-15 min and was spontaneously reversible within a few hours. Although individual subjects were differentially susceptible to lower doses of the drug, all six subjects in this study demonstrated a well-defined statistically significant response at higher doses of the drug. In addition, careful parametric baseline studies were performed in each cat to strengthen the evidentiary linkage between wave A as recorded from the vertex in these experiments and previous studies describing the origin and trajectory of wave A in the brainstem reticular formation and several regions of thalamus, including the intralaminar nuclei. Thus, we conclude that the production of wave A depends substantially on the postsynaptic activation of muscarinic cholinergic receptors whose cells of origin lie within the brainstem reticular formation.

Animals↗
PubMed1990

Effect of alpha2 antagonists and an agonist on EEG slowing induced by scopolamine and lesion of the nucleus basalis.

In the present study, the effects of an alpha 2 agonist (clonidine, 1.0 mg/kg i.p.) and two antagonists (atipamezole, 1 and 10 mg/kg s.c. and yohimbine, 3.0 mg/kg i.p.) were studied on the EEG activity of naive rats, pretreated with either saline or scopolamine (0.8 mg/kg), or rats receiving lesioning of the nucleus basalis. The alpha 2 antagonists increased fast activity (alpha and beta). Clonidine increased slow wave activity (increased in spectral amplitudes) during periods of immobility and mobility. The EEG slowing, induced by scopolamine, was not alleviated by antipamezole or yohimbine, but in immobile rats, an increase in the delta and theta amplitudes was augmented by clonidine. In nucleus basalis-lesioned rats, the increase in delta activity was partially normalised by the alpha 2 antagonists. The decrease in the beta amplitude, induced by lesioning of the nucleus basalis, was not alleviated with either atipamezole or yohimbine. Clonidine increased the slow wave activity in nucleus basalis-lesioned rats and induced an increase in delta and theta bands during immobility. No changes were induced by clonidine in the EEG recorded from rats with lesions of the nucleus basalis.

Adrenergic alpha-Antagonists↗
PubMed1995

Reduction of pain and nausea after laparoscopic sterilization with bupivacaine, metoclopramide, scopolamine, ketorolac, and gastric suctioning.

OBJECTIVE: To determine whether postoperative pain and nausea after laparoscopic sterilization can be reduced with a combination of bupivacaine, metoclopramide, scopolamine, ketorolac, and gastric suctioning. METHODS: Women undergoing outpatient laparoscopic sterilization were randomized to protocol management or nontreatment groups. Each patient received standard general endotracheal anesthesia. Protocol subjects received intramuscular ketorolac 60 mg and scopolamine 0.25 mg, intravenous metoclopramide 10 mg, and gastric suctioning; bupivacaine (2.5 mg/mL) with epinephrine (5 micrograms/mL) was injected at trocar sites and dripped onto the fallopian tubes. The nontreatment group served as controls. Visual analogue scales were used to evaluate pain and nausea (measured in millimeters). Demographic characteristics, postoperative requirements for analgesics and antiemetics, time to discharge, and unscheduled admission were also evaluated. RESULTS: During a 7-month period, 71 women were enrolled. Protocol subjects (N = 35) reported pain severity of 27.9 +/- 19.1 mm (mean +/- standard deviation), whereas controls (N = 36) reported 59.3 +/- 23.3 mm (P < .001). Fourteen protocol patients requested additional pain medication, compared with 29 controls (P < .001). Protocol patients indicated a nausea severity of 9.9 +/- 18.7 mm, whereas the controls reported 38.8 +/- 35.5 mm (P < .001). Only one protocol patient required nausea medication, compared with nine controls (P < .02). Severity of pain correlated with severity of nausea (r = 0.38166, P < .001). Protocol patients were discharged from the outpatient surgery unit in 148.6 +/- 45.0 minutes, compared with 176.4 +/- 58.5 minutes for controls (P < .03). CONCLUSION: This regimen reduced the severity of pain and nausea after outpatient laparoscopic sterilization. The need for additional analgesics and antiemetics was also reduced. Protocol patients were discharged earlier than controls. These benefits seem to accrue without significant risk. We believe that this regimen may also be useful in other ambulatory laparoscopic procedures.

Analgesics, Non-Narcotic↗
PubMed1977

The effects of scopolamine on the temporal control of behavior.

Pigeons were provided access to food once every 75 sec independently of their behavior. The effects of scopolamine hydrobromide on the temporal distribution of locomotor activity during the interfood interval were evaluated on the basis of a recently developed model. Drug-induced changes in activity, as evaluated by the model, showed that scopolamine (a) decreased the effect of postfood inhibition, (b) decreased the effect of terminal behaviors that occur late in the interfood interval and compete or interfere with general activity, (c) decreased the total amount of activity engendered by the appetitive schedule of reinforcement, (d) and appeared to produce an underestimation of time intervals. These effects were systematically related to drug dosage.

Animals↗
PubMed1979

VMH obesity reduced but not reversed by scopolamine methyl nitrate.

Chronic administration of scopolamine methyl nitrate, at doses much greater than required to block vagally mediated insulin secretion, reduced static phase VMH obesity by only 31%. At least 59% of the obesity persisted even when the initially effective dose (0.15 mg/Kg, 4 times/day) was increased eight-fold. The larger dose also did not prevent VMH hyperphagia and weight gain when scopolamine treatment was begun before the lesion. By ten days after the lesion, reduced gastrointestinal motility apparently prevented further weight gain. These results suggest that much of the obesity caused by VMH lesions is independent of vagally mediated insulin secretion or other excess vagal efferent activity. The doses used in this experiment were large in order to provide strong evidence for this conclusion.

Animals↗
PubMed1985

Scopolamine impairs the response-to-change following observation of the environment but not after its exploration by the rat.

The tendency to select the T-maze arm that has been changed in brightness between two successive trials (response-to-change) was investigated in rats injected with scopolamine (Sc) or saline (NaCl) 20 min before the test. In the "passive" version of the test, when in trial 1 rats could inspect the white-black arms through clear partitions blocking the entrance to the arms, a dose of when in trial 1 rats could inspect the white-black arms through clear partitions blocking the entrance to the arms, a dose of 1.0 mg/kg Sc decreased significantly the number of changed arm choices in trial 2, as compared to saline controls. A lower dose of Sc (0.5 mg/kg) was ineffective. In the "active" test version, when in trial 1 the rats were allowed to explore the white-black arms, doses of 1.0 and 2.0 mg/kg Sc did not affect the preference for the changed arm in trial 2. NaCl rats showed a significant preference for the changed arm choices in both tests. The scopolamine effects on response-to-change, i.e., impairment of performance in the passive but not in the active version, were essentially the same as those found by us previously in hippocampal rats.

Adaptation, Psychological↗
PubMed1987

Scopolamine disrupts visual reversal without affecting the first discrimination.

The effect of scopolamine (0.5 mg/kg) was determined in a brightness discrimination test (Y maze) motivated by electrical shocks (escape avoidance). Male adult Sprague Dawley rats were used. Results show that scopolamine impairs significantly the visual reversal without affecting the first brightness discrimination. The qualitative analysis reveals that the anticholinergic drug-induced deficit involves both perseveration, i.e. failure to suppress inappropriate response, and a tendency to adopt a position habit. A parallelism with hippocampal and frontal lobe damage symptoms is discussed and an interpretation in terms of disinhibition and incapacity to solve a more difficult problem is proposed.

Animals↗
PubMed1986

New method for management of detrusor instability: transdermal scopolamine.

We report on the results of a pilot study using transdermal scopolamine in the management of detrusor instability (DI). Numerous agents have been used for the management of DI, however, many are associated with poor patient compliance and significant side effects. We have successfully used transdermal scopolamine on 3 patients with DI with good subjective and objective results.

Aged↗
PubMedDate not supplied

Differential effects of scopolamine and D-amphetamine on avoidance: Strain interactions.

In a discriminated Y-maze avoidance task it was observed that mice of the A/J strain were superior to mice of the DBA/2J strain, which in turn made more avoidance responses than C57BL/6J mice. Moreover, the A strain was also observed to acquire a discrimination problem more readily than either of the other strains. Administration of scopolamine enhanced active avoidance performance in A, but not DBA/2 or C57BL/6 mice. D-Amphetamine improved performance in both A and DBA/2 mice but had negligible effects on the performance of the C57BL/6 strain. Neither drug affected discrimination performance irrespective of strain. In an inhibitory avoidance task the C57BL/6 strain was found to perform more poorly than the A strain which was inferior to DBA/2 mice. Scopolamine disrupted performance in all three strains, while d-amphetamine was found to disrupt the performance of the A and DBA/2 strains only. The results were interpreted in terms of the role of associative and nonassociative effects of shock in modulating avoidance behavior.

Animals↗
PubMedDate not supplied

Dissociation of disinhibitory effects of scopolamine: strain and task factors.

In 3 experiments it was observed that 3 strains of mice (A/J, DBA/2J and C57BL/6J) differing in activity exhibited comparable levels of spontaneous alternation, and that scopolamine differentially affected activity in the strains, but uniformly eliminated shock-induced suppression and spontaneous alternation behavior. Data are discussed in terms of the relationship between activity and spontaneous alternation. It was suggested that scopolamine exerts its effects on spontaneous alternation via the effects on acetylcholine activity, independent of any effects on general activity levels.

Animals↗
PubMed1976

Effect of scopolamine on the reactivity of the albino rat to footshock.

To determine if anticholergic drugs altered reactions to footshock, 9 female albino rats were tested for escape latencies following unsignaled presentations of footshock in a two-chambered shuttlebox. Different intensities of footshock (0, 0.04, 0.07, and 0.10 ma) were varied orthogonally with various doses of intraperitoneally injected scopolamine hydrobromide (0, 1.0, 4.0 and 16.0 mg/kg). Shock trials were randomly alternated with nonshock (pseudoshock) trials to estimate any drug-induced activity increase which might occur independently of any alteration in reactivity to aversive stimulation. Results indicated that scopolamine produced a significant increase in reactivity to footshock (i.e., shorter escape latencies) at near-threshold intensities as well as producing the expected increase in general activity.

Animals↗
PubMed1981

Increases in skin resistance of white rats following scopolamine injection.

Thirty-six male albino rats were injected with either saline or 0.6 mg/kg scopolamine and placed on a metal grid. The grid was wired to a transistor-biased detector which determined, every second, whether the subject's resistance was above or below a preset threshold value. Over test sessions of five minutes, drug subject's resistances were above each of the three threshold values used (5, 10, 15 megohms) for significantly longer than those of control subjects. Scopolamine treated rats would therefore receive lower shock levels than control subjects in a shock experiment.

Animals↗
PubMed1984

Differential effects of scopolamine on working and reference memory of rats in the radial maze.

Anticholinergics have often been found to impair choice accuracy in the radial maze. Some researchers have suggested that this indicates involvement of cholinergically innervated structures in cognitive mapping while others argue that these structures mediate working memory. However, most results are open to either interpretation since the baiting method did not allow a distinction between reference and working memory errors. To further test these hypotheses this study examined the effects of systemic scopolamine on radial maze performance, using a 4-out-of-8 baiting procedure. Food-deprived Wistar rats were pretrained until working memory choice accuracy stabilized to a criterion of 87% or better. Scopolamine (0.1, 0.4 and 0.8 mg/kg, IP, 30 min before a session) significantly increased the number of working memory errors (re-entries into baited arms) whereas reference memory errors (entries into never baited arms) did not change significantly. Observed deficits appeared not to be attributable to a drug-induced disruption of motivational systems. Results confirm the behavioural similarities between the memorial effects of hippocampectomy and anticholinergics, and implicate cholinergically innervated structures in working memory.

Animals↗
PubMed1984

Differential effects of d-amphetamine and scopolamine on the ontogeny of rearing.

Although rearing is ontogenetically an important behavior, very little is known about the neural bases of rearing. The role development of catecholaminergic and cholinergic neurons play in the ontogeny of rearing was investigated by examining rearing in infant, adolescent, and adult rats following various doses of d-amphetamine (an indirectly acting catecholaminergic agonist) and scopolamine (a cholinergic muscarinic receptor antagonist). d-Amphetamine increased rearing in infants but not in adolescents and adults. These findings suggest that activation of catecholaminergic neurons increases rearing in infants but not in adolescents or adults. Scopolamine increased rearing in adolescents and adults but not in infants, indicating that blocking transmission of cholinergic neurons increases rearing in only older rats.

Aging↗
PubMed1986

Effects of scopolamine and unilateral lesions of the basal forebrain on T-maze spatial discrimination and alternation in rats.

Cholinergic systems are thought to play a role in memory. It has been suggested that cholinergic neurons, possibly the cortically projecting cells of the nucleus basalis magnocellularis, are differentially involved in working and reference memory. To evaluate this hypothesis the effects on memory of scopolamine (0, 0.3, 0.6 mg/kg) or unilateral kainic acid (4.7 nmoles in 1 microliter) lesions of the basal forebrain of rats were tested. Working memory, the recall of recent events of transient importance that is vulnerable to interference, was tested using a T-maze alternation task; reference memory, information stored over the long term that is relatively resistant to interference, was evaluated using a spatial discrimination task in the T-maze. The differential sensitivity of the two tasks to interference effects was confirmed by the finding that the insertion of a 30-sec delay between trials significantly reduced performance in the alternation but not the spatial discrimination task. Furthermore, scopolamine or the lesions significantly impaired alternation but not spatial discrimination performance. Biochemical assays of the kainate-injected brains confirmed that the cortical cholinergic marker, choline acetyltransferase, was significantly reduced. These results support the hypothesis that working and reference memory may be differentially controlled by cholinergic systems.

Animals↗