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Biomedical subjects

S C Dilsaver

Publications and source records attributed to S C Dilsaver.

At least 37 records · Page 2Linked to original sources
PubMed1994

Withdrawal phenomena associated with antidepressant and antipsychotic agents.

The withdrawal of heterocyclic antidepressants and antipsychotic agents can produce nausea, emesis, anorexia, diarrhoea, rhinorrhoea, diaphoresis, myalgias, paraesthesias, anxiety, agitation, restlessness and insomnia. The withdrawal of monoamine oxidase (MAO) inhibitors may result in severe anxiety, agitation, pressured speech, sleeplessness or drowsiness, hallucinations, cognitive impairment, delirium, suicidality and delusions of persecution. The withdrawal of antipsychotic agents may give rise to symptoms preceding the onset of psychosis. These potential harbingers of relapse include anxiety, agitation, restlessness and insomnia. The withdrawal phenomena reviewed are usually prevented by gradually reducing the total daily dosage of the pertinent drug. Antimuscarinic agents often alleviate the distress produced by the withdrawal of tricyclic antidepressants and antipsychotic agents. MAO inhibitor withdrawal syndromes may constitute medical emergencies. The prevention of the evolution of a MAO inhibitor withdrawal-precipitated syndrome is a high priority.

Adult↗
PubMed1993

Treatment with carbamazepine may enhance alpha 2-noradrenergic autoreceptor sensitivity.

Chronic, not acute treatment with carbamazepine enhanced the hypothermic response to a dose of clonidine thought to exert its predominant effect on the presynaptic alpha 2-autoreceptor. This response was markedly elevated both during the course of and 10 days after the discontinuation of treatment with carbamazepine. Sensitivity to clonidine returned to baseline 10 to 21 days after the discontinuation of treatment. Carbamazepine is the first treatment for the disorders of mood that has been demonstrated to enhance a physiological response to clonidine. The authors discuss the theoretical relationship between increased sensitivity of the presynaptic alpha 2-autoreceptor and the usefulness of carbamazepine in the treatment of bipolar disorder.

Animals↗
PubMed1993

Chronic treatment with valproate decreases the hypothermic response to clonidine.

Treatment with lithium (the prototype of an antimanic agent) attenuates responsiveness to the alpha 2-agonist clonidine in animal models. Valproate is now used to treat mania. The effect of treatment with this drug on responses mediated by an alpha 2-agonist have yet to be reported. The authors assessed the effect of a 14-day course of orally administered valproate on the rat's hypothermic response to clonidine. Treatment with valproate decreased this response.

Animals↗
PubMed1993

Phenelzine produces subsensitivity to nicotine.

1. The authors attempted to detect a possible effect of treatment with phenelzine on a physiological response to nicotine in the rat. 2. Positive findings in an animal model suggest the feasibility of more complicated experiments in animals and the possibility of studies involving human subjects. 3. Treatment of Sprague Dawley rats (n = 10) with phenelzine sulfate (15.0 mg/kg ip) every 48 hours for 14 days was associated with a 73.3% decrease in the hypothermic response to nicotine. 4. Treatment with phenelzine did not enhance the rate of elimination of nicotine. 5. The authors discuss a possible relationship between changes in nicotinic mechanisms and the therapeutic actions of drugs used to treat affective illness.

Animals↗
PubMed1993

Depressive mania associated with nonresponse to antimanic agents.

Of 39 patients consecutively admitted for the treatment of primary mania, 21 (53.8%) simultaneously met the Research Diagnostic Criteria for major depressive disorder ("mixed" or "depressive" mania). Only nine (42.9%) of the 21 patients with depressive mania responded to antimanic agents. In contrast, 16 (88.9%) of the 18 patients with pure mania responded to these drugs. This finding is consistent with previous reports suggesting that the mixed state is a virulent form of mania.

Adult↗
PubMed1993

Comorbid panic disorder in patients with winter depression.

This study investigated the prevalence of comorbid panic disorder in patients with recurrent wintertime episodes of major depression. The subjects were 38 patients (10 male and 28 female) who met the DSM-III-R criteria for major depression with a seasonal pattern (wintertime depression). Diagnoses of panic disorder were made according to the DSM-III-R criteria. Nine (23.7%) of the subjects (four women and five men) met the criteria for panic disorder. Their panic attacks and depressive symptoms had simultaneous onset in the fall or winter and remitted spontaneously in the spring. Patients with winter depression appear to be at high risk for simultaneous panic disorder, consistent with results from studies in which season of illness was not considered.

Adult↗
PubMed1993

State-dependent pain in winter depression.

The incidence and nature of state-dependent pain were investigated in 43 consecutively presenting patients with recurrent autumn/winter episodes of major depression followed by spontaneous recovery in the spring. Twenty-two (51.2%) experienced state-dependent pain, which appears to be a common concomitant of wintertime depression.

Adult↗
PubMed1993

Antipsychotic agents: a review.

Antipsychotic agents are useful in the treatment of psychosis due to both functional disorders (i.e., idiopathic disorders that are usually treated by psychiatrists) and organic mental disorders. These drugs are classified as low- and high-potency agents. Low-potency agents such as chlorpromazine block muscarinic and alpha 1-adrenergic receptors. Consequently, they produce anticholinergic side effects and orthostatic hypotension. High-potency antipsychotic agents have a higher affinity for dopamine receptors and a relatively negligible affinity for muscarinic and alpha 1 receptors. The high-potency agents frequently cause extrapyramidal side effects, such as dystonia and parkinsonism. Serious reactions to antipsychotic drugs include tardive dyskinesia and neuroleptic malignant syndrome.

Dyskinesia, Drug-Induced↗
PubMed1993

Tranylcypromine withdrawal phenomena.

The gradual or abrupt withdrawal of tranylcypromine can result in syndromes ranging in severity from mild discomfort to incapacitation. Five patients were subjected to the withdrawal of tranylcypromine. Vignettes describing the withdrawal syndrome experienced by these patients are presented. These patients suffered from severe depression or impairment of cognition in association with a reduction in their daily dose of tranylcypromine. The authors conclude that reductions in a patient's dose or the discontinuation of tranylcypromine warrant the careful supervision of a physician.

Acute Disease↗
PubMed1993

The manic syndrome: factors which may predict a patient's response to lithium, carbamazepine and valproate.

Studies suggest that 80% to 90% of all patients in the manic state respond to lithium provided that they are relatively free of dysphoria ("pure mania"). In contrast, less than 40% of individuals in the manic state who cycle rapidly or are substantially dysphoric ("dysphoric mania") respond to lithium. These patients appear to be more responsive to carbamazepine and valproate. The authors conclude that carbamazepine and valproate are the drugs of choice if one desires to treat a rapidly cycling individual or patient with dysphoric mania with just one agent. However, they emphasize that a prospective study designed to identify the predictors of response of primary mania to lithium, carbamazepine and valproate is required. Studies assessing the relative value of lithium, carbamazepine or valproate as prophylactic agents in the care of patients with specific subtypes of mania are also needed. These studies would address the most important issues confronting researchers interested in the drug treatment of mania.

Bipolar Disorder↗
PubMed1992

The Flinders Sensitive Line exhibits enhanced thermic responsiveness to nicotine relative to the Sprague-Dawley rat.

The Flinders Sensitive Line (FSL) was derived from the Sprague-Dawley rat by selectively breeding animals with heightened sensitivity to an anticholinesterase. The FSL now consistently exhibits enhanced behavioral and physiological responses to muscarinic agonists relative to its progenitor. The authors now report the FSL exhibits enhanced thermic responsiveness to nicotine relative to the Sprague-Dawley rat. The possible relevance of this finding to investigators interested in the disorders of mood is briefly discussed.

Animals↗
PubMed1992

Measurement of temperature in the rat by rectal probe and telemetry yields compatible results.

The change in body temperature of the rat is commonly measured using biotelemetry or the rectal probe. The authors report that the two methods yield qualitatively similar but quantitatively different results in two experiments. In Experiment 1, both methods detected a salicylate-affected reduction in handling-induced hyperthermia. In Experiment 2, both methods were useful in detecting the hypothermia induced by the muscarinic agonist oxotremorine. In both Experiments 1 and 2, measurements of baseline temperature were higher when measured with the rectal probe. Baseline temperature is measured with biotelemetry prior to handling animals, whereas the act of measuring baseline temperature with the rectal probe necessitates handling. The investigators hypothesized that a rise in baseline temperature produced by handling at least partially accounts for the greater hypothermic response obtained in Experiment 2 using measurements obtained with the rectal probe. In Experiment 3, baseline temperature was measured with biotelemetry after animals were handled. Handling produced an increase in baseline temperature. The hypothermic response to oxotremorine was increased when the higher posthandling baseline temperature was used to calculate the hypothermic response of animals. The authors conclude that differences in baseline temperature and hypothermic response obtained with the two methods are related to an effect of handling.

Animals↗
PubMed1992

Secondary social phobia in patients with major depression.

Nineteen of 42 (45.2%) patients were socially phobic when and only when depressed. Each of these patients met diagnostic criteria for primary depression (Research Diagnostic Criteria) and major depression (DSM-III-R). Every subject had three or more distinct episodes of depression. Eight of the 9 men (88.9%) and 11 of the 33 women (33.3%) were socially phobic when depressed (p = 0.004). Patients with recurrent wintertime episodes of major depression (p = 0.036) and a past history of alcohol or drug abuse were more likely to be socially phobic (p = 0.0001). The authors suggest the 19 socially phobic patients with primary depression should be regarded as having secondary social phobia. Secondary social phobia may be an important source of comorbidity in patients with primary depression.

Adult↗
PubMed1992

Chronic treatment with ethanol alters the physiological action of nicotine.

1. Ethanol decreases the release of acetylcholine through effects on presynaptic neurons at both muscarinic and nicotinic junctions. 2. Blockade of the release of acetylcholine should produce denervation supersensitivity at both muscarinic and nicotinic cholinergic junctions. 3. Chronic but not acute treatment with ethanol produces supersensitivity to the hypothermic effects of a muscarinic agonist in the rat. 4. The authors now report that chronic treatment with orally administered ethanol blunts (rather than enhances) the hypothermic response to nicotine in the rat. 5. This could have major public health implications. 6. Smoking and the use of ethanol containing beverages positively covary. 7. Ethanol induced reduction in sensitivity to nicotine suggests that the heavy consumption of ethanol may necessitate that one drink more than otherwise in order to obtain the desired effects of nicotine.

Animals↗
PubMed1992

Bidirectional effect of beta-carboline agonists at the benzodiazepine-GABAA receptor chloride ionophore complex on GABA-stimulated 36Cl- uptake.

beta-Carboline agonists produced a left shift of the GABA concentration-chloride uptake curve or a reduction in the maximal increase in GABA-stimulated 36Cl- uptake depending on their concentration. The enhancement of the GABA effect occurs only at lower beta-carboline and GABA concentrations and is smaller for the partial agonist ZK 9126 compared to the full agonist ZK 93423. The opposite effect, inhibition of GABA-stimulated chloride conductance, is observed only at higher concentrations of beta-carboline agonists and GABA. The reduction of the GABA maximal response by the partial agonist ZK 91296 is greater than by the full agonist ZK 93423. The transformation of GABA-stimulated 36Cl- uptake data to specific chloride influx (36Cl- uptake per nM of GABA) reveals that the GABA concentration-response curve consists of three parts characterized by differences in the molar effectiveness of GABA relative to the GABA concentration. The molar effectiveness of GABA is a measure of the sensitivity of the GABAA receptor chloride ionophore complex and shows adaptive changes by this complex to increasing concentrations of GABA and/or beta-carboline. We conclude from our data that the change from GABA-sensitive to GABA-insensitive conformation of the GABAA receptor occurs with increasing concentrations of GABA and/or beta-carboline. Both conformations maintain positive heterotropic cooperativity with beta-carboline binding sites, one responsible for positive and the other responsible for negative effects of beta-carboline agonists on chloride uptake.

Animals↗
PubMed1992

Differentiating organic from functional psychosis.

Psychosis is not pathognomonic of psychiatric illness. It is simply a nonspecific cluster of signs and symptoms that may occur in a broad array of medical, neurologic and surgical disorders or as a consequence of pharmacologic treatment, substance abuse or the withdrawal of drugs and alcohol. Psychoses are classified as organic or functional mental disorders. Organic disorders with psychosis are caused by structural defects or physiologic dysfunction of the brain. The causes of functional disorders have not yet been identified. Psychoses are also categorized as effective or nonaffective in character. Affective and nonaffective psychoses may be associated with either organic or functional disorders.

Affective Disorders, Psychotic↗