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Biomedical subjects

E A Mueller

Publications and source records attributed to E A Mueller.

At least 73 records · Page 4Linked to original sources
PubMed1988

Induction of migrainelike headaches by the serotonin agonist m-chlorophenylpiperazine.

In a study of serotonin (5-HT) function in patients with eating disorders and healthy control subjects, severe headaches with features of common migraine occurred unexpectedly in 28 of 52 subjects (54%) 8 to 12 hours after receiving a single oral dose of the 5-HT receptor agonist m-chlorophenylpiperazine (m-CPP), 0.5 mg/kg. None of the same subjects developed similar late-occurring headaches after placebo or the 5-HT precursor, L-tryptophan, 100 mg/kg given intravenously. The frequency of these migrainelike headaches was not significantly different between patients with bulimia or anorexia nervosa and control subjects, but incidence of headaches was significantly greater in subjects with a personal or family history of migraine, with almost all predisposed individuals (18 of 20, 90%) developing severe symptoms. Headache ratings were also significantly correlated (rho = 0.70; p less than 0.0001) with peak concentrations of m-CPP in plasma. These observations indicate that m-CPP may provide a novel probe for studies of the pathophysiology of migraine headaches.

Adult↗
PubMed1988

A new scale for the assessment of depressed mood in demented patients.

Twenty-one subjects with clinically diagnosed dementia of the Alzheimer type were rated on the Dementia Mood Assessment Scale, a new instrument intended to measure the severity of depressed mood in cognitively impaired patients. Ratings were based on direct observation and a semistructured interview of the patient. Interrater reliability was established. There were highly significant correlations between patients' scores on the instrument's 17-item depression subscale and their scores on global measures of depression and sadness. The potential usefulness of this new scale in assessing the severity of depression in demented patients longitudinally or under drug treatment conditions is discussed.

Adult↗
PubMed1988

Tranylcypromine compared with L-deprenyl in Alzheimer's disease.

The authors have previously reported mild improvement of behavior and cognition in a group of 17 nondepressed patients with dementia of the Alzheimer type (DAT) treated with two doses of L-deprenyl (10 and 40 mg/day). Seven of these patients subsequently received double-blind, placebo-controlled treatment with tranylcypromine. The patients experienced significant side effects, particularly orthostatic hypotension without compensatory pulse increase, during tranylcypromine treatment. These effects were more severe than those occurring during L-deprenyl treatment, and they occurred at substantially lower doses (mean dose, 16 mg/day). These data support the role of the inhibition of monoamine oxidase type A in the development of orthostatic hypotension in patients treated with monoamine oxidase inhibitors. They also raise the question of whether the observed sensitivity to monoamine oxidase inhibition is a function of age or disease. In either case, the greater toxicity of tranylcypromine makes inferences difficult regarding the relative efficacies of these drugs in treating patients with dementia of the Alzheimer type and may limit the potential usefulness of tranylcypromine in ameliorating some symptoms of this disease.

Aged↗
PubMed1987

Anticholinergic sensitivity in patients with dementia of the Alzheimer type and age-matched controls. A dose-response study.

We compared the cognitive and behavioral responses to three intravenous doses of scopolamine (0.1, 0.25, and 0.5 mg) and placebo of ten patients with dementia of the Alzheimer type (DAT) and ten age- and sex-matched elderly control subjects. The patients with DAT showed significant behavioral and cognitive but not physiologic changes at a lower scopolamine dose (0.25 mg) than did the normal elderly controls. Cognitive tests of new learning and semantic knowledge revealed significant impairments at the 0.25-mg scopolamine dose in the patients with DAT, while the responses of the control population were essentially unchanged. Behaviorally, mild euphoria, motor incoordination, and hostility occurred in the patients with DAT but not the controls at the 0.25-mg dose. These differences were unrelated to peripheral physiologic changes produced by the different scopolamine doses. These results indicate that central nervous system functions such as cognition and certain elements of behavior are more sensitive to temporary cholinergic blockade in patients with DAT than in normal age-matched controls. We review implications concerning the status of central cholinergic function in patients with DAT in light of neuropathologically demonstrated cholinergic system lesions in DAT.

Age Factors↗
PubMed1987

L-deprenyl in Alzheimer's disease. Preliminary evidence for behavioral change with monoamine oxidase B inhibition.

Since monoamine neurotransmitter disturbances exist in some cases of dementia of the Alzheimer's type (DAT), monoamine-enhancing drugs may ameliorate some symptoms of DAT. L-Deprenyl is a monoamine oxidase (MAO) inhibitor that is generally free of undesired effects. At low doses (10 mg/d) it selectively inhibits MAO-B, an enzyme whose level is elevated in the brains of patients with DAT who are studied post mortem. At higher doses it has more complex effects, including inhibition of MAO-A plus MAO-B. We administered 10 mg/d and 40 mg/d of L-deprenyl to 17 patients with DAT in a double-blind, placebo-controlled, serial treatment. Total Brief Psychiatric Rating Scale scores decreased significantly during 10-mg/d treatment, with decreases in measures of anxiety/depression, tension, and excitement. Approximately one half of the patients' conditions were judged to be improved clinically, with evidence of increased activity and social interaction along with reduced tension and retardation. Similar but smaller changes were observed during 40-mg/d treatment. The behavioral changes were associated with improvement in performance on a complex cognitive task requiring sustained effort. There were minimal physiologic and side effects. The greater effect of low-dose L-deprenyl therapy suggests that it is the inhibition of MAO-B, and not MAO-A, that may be important in the behavioral effects of L-deprenyl administration to patients with DAT.

Adult↗
PubMed1987

Serotonergic responsivity in obsessive-compulsive disorder. Comparison of patients and healthy controls.

To examine the "serotonin hypothesis" of obsessive-compulsive disorder (OCD), we studied the behavioral and neuroendocrine effects of metachlorophenylpiperazine (mCPP), a serotonergic agonist, in patients with OCD and healthy controls. Twelve patients and 20 controls were given a single dose of 0.5 mg/kg of mCPP, administered orally under double-blind, placebo-controlled, random-assignment conditions. Following mCPP, but not following placebo, patients with OCD experienced a transient but marked exacerbation of obsessive-compulsive symptoms. Moreover, compared with healthy controls, patients exhibited greater other behavioral (but not endocrinologic or thermal) changes after mCPP. These findings are consistent with a special role for the neurotransmitter serotonin in OCD psychopathology.

Adult↗
PubMed1987

Dose-dependent effects of deprenyl on CSF monoamine metabolites in patients with Alzheimer's disease.

Deprenyl, a monoamine oxidase (MAO) inhibitor with selective effects on MAO type-B at low doses, was administered to 13 patients with dementia of the Alzheimer type (DAT), a disorder reported to be associated with increased brain MAO-B activity. Cerebrospinal fluid was obtained for measurement of three monoamine metabolites, homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglycol (MHPG), by high pressure liquid chromatography with electrochemical detection. Deprenyl treatment (10 mg/day) for 3-4 weeks was associated with small but statistically significant reductions in HVA (21%) and 5-HIAA (15%) compared to baseline values. Subsequent administration of deprenyl at the higher dose of 40 mg/day for 3-4 more weeks led to greater reductions in HVA (40%) and MHPG (43%) than 5-HIAA (20%). These dose-dependent reductions are consistent with in vitro biochemical and anatomical data from primate brain suggesting that at low doses of deprenyl, MAO-B inhibition might be expected to selectively affect dopamine and serotonin-containing neurons, while at higher doses (which lead to MAO-A as well as MAO-B inhibition), noradrenergic neurons may become relatively more affected by the drug.

Aging↗
PubMed1987

CSF somatostatin in patients with Alzheimer's disease, older depressed patients, and age-matched control subjects.

Somatostatin-like immunoreactivity was measured in the CSF of 12 patients with Alzheimer's disease, 15 age-matched control subjects, and 20 older depressed subjects. Patients with dementia or depression were found to have lower CSF somatostatin concentrations than control subjects despite markedly different clinical presentations. Severity of depression was clearly different in all three groups but showed no significant correlation with CSF concentration of somatostatin. There was a significant positive correlation between CSF somatostatin-like immunoreactivity and cognitive functioning in all 47 subjects, but this association was not statistically significant within individual diagnostic groups. These data raise interesting questions about possible biological links between Alzheimer's disease and depression in older patients.

Age Factors↗
PubMed1986

Further studies of the putative serotonin agonist, m-chlorophenylpiperazine: evidence for a serotonin receptor mediated mechanism of action in humans.

To further evaluate the effects and mechanism of action of the putative serotonin agonist m-chlorophenylpiperazine (m-CPP) in humans, changes in plasma prolactin, cortisol, growth hormone, ACTH and body temperature were studied in a group of 10 healthy volunteers following oral administration of m-CPP (0.75 mg/kg), before and after pretreatment with the serotonin receptor antagonist metergoline (MTG). M-CPP produced transient significant increases in plasma prolactin, cortisol, ACTH and in body temperature, but did not significantly alter plasma growth hormone concentration. Moreover, pretreatment with the 5HT antagonist metergoline blocked the m-CPP-induced hormonal and temperature changes. These findings provide strong support for m-CPP's effects in humans being mediated through an interaction with 5HT receptors, and thus support the usefulness of m-CPP as a pharmacologic tool for studying disease and drug-induced alterations in serotonin function in man.

Adrenocorticotropic Hormone↗
PubMed1986

Pharmacologic modelling of Alzheimer's disease.

Evidence pointing to the central role of the cholinergic system in normal human memory function and disorders such as Alzheimer's disease has grown tremendously in recent years. Anticholinergic and non-cholinergic agents have been found to create transient memory impairments in young adults which mimic the changes associated with normal aging or amnesia. The rationale for using scopolamine, a centrally active anticholinergic agent, as a pharmacologic probe of memory function is reviewed using data from studies in animals and humans. The cognitive functioning of normal elderly controls given scopolamine is compared to the baseline functioning of patients with Alzheimer's disease, followed by a discussion of the use of scopolamine as a modelling agent for dementia.

Adult↗
PubMed1986

Use of serotonergic agents in the clinical assessment of central serotonin function.

To assess the status of the brain serotonergic system in relation to ongoing behavior, agents with predominant actions on serotonin synthesis, release, uptake, and receptor mechanisms are being evaluated. Abnormalities in the neuroendocrine responses to tryptophan, 5-hydroxytryptophan, fenfluramine, and m-chlorophenylpiperazine are under exploration in depressed patients. These agents are also being used to assess postulated changes in serotonin metabolism and serotonin receptor adaptation during longer term treatment with antidepressant drugs, lithium, and other psychoactive agents. Concurrent studies in rodent and nonhuman primate models are helping to validate these approaches to the exploration of the role of serotonin in psychiatric and neurologic disorders.

5-Hydroxytryptophan↗
PubMed1986

Rapid antidepressant effect of addition of lithium to tranylcypromine.

A chronically depressed patient who had not responded to treatment with several tricyclic antidepressants and monoamine oxidase inhibitors alone, responded within hours following the addition of lithium to ongoing tranylcypromine treatment in a double-blind medication trial. The findings are discussed in the context of reports of lithium augmentation of other antidepressants.

Depressive Disorder↗
PubMed1985

Tyramine pressor sensitivity changes during deprenyl treatment.

Deprenyl has previously been reported to be a selective monoamine oxidase (MAO) type B inhibitor, which is associated with little or no enhancement of the pressor effects of tyramine. Employing an intravenous steady-state tyramine infusion technique, the effects of different doses of deprenyl and, for comparison, the mixed inhibitor tranylcypromine on the pressor response to tyramine were studied in 11 depressed patients. After 3 weeks of treatment, deprenyl produced dose-proportionate increases in tyramine sensitivity at all three doses (10, 30, and 60 mg/day) when compared to placebo baseline tyramine responses. While only a modest (3.7-fold) increase in tyramine sensitivity was found with the 10 mg/day deprenyl dose, the increase in tyramine sensitivity at the 60 mg/day dose of deprenyl (22-fold) approached that found with tranylcypromine. Reductions in plasma 3-methoxy,4-hydroxyphenylglycol (MHPG), used as a possible index of in vivo MAO-A inhibition, were highly correlated with increases in tyramine pressor sensitivity (r = 0.82). The data suggest that deprenyl acts as a relatively selective MAO-B inhibitor at low doses, but that this selectivity is lost at higher doses, resulting in a significant "crossover" inhibition of MAO-A and increased tyramine pressor sensitivity.

Blood Pressure↗
PubMed1985

Scopolamine challenges in Alzheimer's disease.

A challenge paradigm was designed to test the functional sensitivity to anticholinergic agents in Alzheimer's disease. Ten patients with dementia of the Alzheimer type were serially administered three different intravenous doses of the centrally active anticholinergic drug scopolamine and placebo. Testing was carried out in a placebo-controlled, double-blind fashion to measure cognitive, physiologic and behavioral changes. Alzheimer patients showed a marked, dose-related behavioral and cognitive sensitivity to temporary cholinergic blockade. Scopolamine testing may serve as an index of the status of central cholinergic functional integrity, and ultimately may prove useful as a diagnostic or staging test in the evaluation of the cholinergic system in dementia. Research is currently under way with elderly age-matched controls and populations with other neuropsychiatric disorders to explore this hypothesis further.

Adult↗
PubMed1985

Obsessive-compulsive disorder and serotonin: is there a connection?

Reports of the antiobsessional efficacy of clomipramine have led to a "serotonin hypothesis" of obsessive-compulsive disorder (OCD). To test this hypothesis, 16 outpatients with DSM-III OCD were studied using several measures of serotonergic function. Platelet 3H-imipramine binding and serotonin uptake were not significantly different between the OCD patients and a normal, age-matched control group. The level of the metabolite 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) was significantly higher in a small cohort of obsessionals compared with healthy volunteers, possibly reflecting increased brain serotonin turnover. In a direct test of the role of serotonin uptake in clomipramine's antiobsessional effects, the serotonin uptake inhibitor zimelidine was compared with the noradrenergic uptake inhibitor desipramine in a double-blind, controlled study. Zimelidine reduced CSF 5-HIAA, but was clinically ineffective in this group. Desipramine had weak but significant clinical effects. Nonresponders to zimelidine or desipramine improved significantly during a subsequent double blind trial of clomipramine. These findings demonstrate that pharmacological blockade of serotonin reuptake alone is not sufficient for an antiobsessional response.

Adult↗
PubMed1985

TRH stimulation test in dementia of the Alzheimer type and elderly controls.

Dementia of the Alzheimer type (DAT) is known to be a heterogeneous syndrome with many clinical manifestations, including depression. In the present study, the thyrotropin-releasing hormone (TRH) stimulation test, previously used as a possible biological marker of depression, was administered to 15 DAT patients and 10 elderly controls. Seven out of 15 (47%) of the patients but none of the controls showed a blunted response with maximal changes of thyroid-stimulating hormone (TSH) from baseline of less than or equal to 7 microIU/ml following injection of 500 micrograms of TRH. The degree of blunting did not correlate with concurrent depression ratings.

Adult↗
PubMed1985

Tricyclic response in obsessive compulsive disorder.

Therapeutic responses to the tricyclic antidepressant clomipramine have been demonstrated in five double blind studies of patients with obsessive compulsive disorder. Biological alterations in patients with obsessive compulsive disorder resemble those of depressed patients for the dexamethasone suppression test, for some measures of sleep physiology, and in similar neuroendocrine responses to clonidine. Clomipramine's antiobsessional effect does not require high baseline depression ratings or biological abnormalities similar to those seen in depressives. Preliminary results suggest that in contrast to depressives, patients with obsessive compulsive disorder may respond to clomipramine but not to the tricyclic antidepressant desipramine.

Adolescent↗