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Biomedical subjects

D Pickar

Publications and source records attributed to D Pickar.

At least 217 records · Page 12Linked to original sources
PubMed1984

Prazosin, a specific alpha 1-noradrenergic receptor antagonist, has no effect on symptoms but increases autonomic arousal in schizophrenic patients.

The specific alpha 1-noradrenergic antagonist, prazosin, was administered to seven schizophrenic patients in a double-blind, placebo-controlled trial. Patients showed no change in any of their psychiatric symptoms as rated by nurses on global depression and psychosis scales and by physicians on the Brief Psychiatric Rating Scale. However, they did show a significant increase in autonomic arousal as measured by changes in skin conductance. The increased autonomic arousal is probably mediated by increases in plasma norepinephrine induced by chronic prazosin treatment.

Adolescent↗
PubMed1984

Plasma cortisol and beta-endorphin immunoreactivity in nonmajor and major depression.

Plasma cortisol levels of 28 hospitalized patients meeting Research Diagnostic Criteria for major or nonmajor (minor or intermittent) depression were significantly higher than those of eight normal subjects. In contrast, plasma beta-endorphin immunoreactivity was significantly lower in patients with nonmajor depression than in those with major depression or in normal subjects. A low ratio of plasma beta-endorphin to cortisol immunoreactivity was found to characterize patients in both groups. Through the use of only this ratio, a post-hoc analysis identified 25 depressed patients and seven controls. These findings have implications for psychiatric diagnosis and the involvement of the endogenous opioid system in the pathogenesis of depression.

Adult↗
PubMed1984

Attempted suicide in chronic schizophrenia.

In a consecutive series of 127 chronic schizophrenics admitted to hospital, 70 (55.1 per cent) had attempted suicide. When compared with the chronic schizophrenics who had not attempted suicide, significantly more of the attempters had had a major depressive episode (45.7 per cent) and had received antidepressant medication (65.7 per cent). They also had histories of significantly more psychiatric admissions (a mean of 5.4 compared with 3.6). These findings are discussed.

Adolescent↗
PubMed1984

High dose naloxone in depression.

The behavioral effects of a 2 mg/kg iv bolus infusion of naloxone were compared with a placebo infusion using a double-blind design in a small group of inpatient depressives (n = 6) and normals (n = 8). Naloxone produced consistent and significant worsening in the rated signs and subjective symptoms of depression in the patients. In the normals, lesser changes in Hamilton depression and BPRS total scores were observed while none of the subjective scales were significantly altered. The data suggest that depressives manifest a more marked and subjectively more intense response to naloxone compared to normals. Further studies are required to confirm this preliminary finding and to clarify its relationship to the pathogenesis of depression.

Adult↗
PubMed1983

High-dose naloxone infusions in normals. Dose-dependent behavioral, hormonal, and physiological responses.

Hypotheses of involvement of the endogenous opioid system (EOS) in the regulation of human behavior suggest that functional blockade of the EOS should have behavioral consequences. Clinical administration of the opiate receptor antagonist naloxone hydrochloride, however, has had little or inconsistent behavioral effects in normals. This may be attributable to the use of doses insufficient to yield a complete EOS blockade. To assess this explanation, normals were administered increasing doses of naloxone hydrochloride (0.3 to 4 mg/kg) in a single-blind design. Significant dose-dependent behavioral, hormonal, and physiological effects were found. With increasing doses of naloxone, volunteers demonstrated increasingly dysphoric affects, a deterioration of performance on memory testing, increasing systolic BP and respiratory rate, and increasing plasma cortisol and growth hormone levels. These results are consistent with the expected effects of increasing EOS blockade, and thus suggest that lower doses of naloxone used in previous clinical studies may not have been sufficient to produce a complete EOS blockade. Specifically, they suggest involvement of the EOS in the tonic regulation of normal human mood, memory, BP, respirations, and plasma growth hormone and cortisol levels.

Adult↗
PubMed1983

Pain enhances naloxone-induced hyperalgesia in humans as assessed by somatosensory evoked potentials.

The effect of 8 mg IV naloxone on pain appreciation was studied with electric shocks administered to the left forearm of 20 normal volunteers. Pain sensitivity was assessed with a psychophysical task and with evoked potentials (EP) to the pain stimuli which were found sensitive to opiate agonists and antagonists in previous experiments. Naloxone-induced hyperalgesia before and after 20 min of intermittent shock was assessed in a 3-day placebo crossover experiment designed to provide control comparisons of time effects. EP amplitude enhancement with naloxone was significantly greater following 20 min of shocks than preceding them, while pain judgments were not significantly affected. Thus, naloxone increases pain sensitivity, especially after prolonged pain stimulation. This finding is consistent with endorphin mediation of stress-induced analgesia and raises the question of whether this type of response decrement over time is related to the phenomena of habituation.

Adult↗
PubMed1983

The relationship of plasma cortisol and beta-endorphin immunoreactivity to surgical stress and postoperative analgesic requirement.

It has been hypothesized that the endogenous opioid (endorphin) system is related to biologic stress responses. We have used general surgery as a naturalistic model for studying stress response in humans. Abdominal surgery, but not anesthesia induction, was associated with significant increases in plasma beta-endorphin immunoreactivity and cortisol. Both hormones decreased significantly during post-operative morphine administration. Baseline and mean surgery levels of plasma beta-endorphin immunoreactivity showed an inverse relationship with post-operative analgesic requirement. These data support involvement of the endorphin system in human stress response and in human endogenous analgesic mechanisms. Findings also support the concept that baseline or psychologically stimulated levels of arousal may also be an important determinant in the physiology of stress response and pain perception.

Adolescent↗
PubMed1983

High-dose naloxone affects task performance in normal subjects.

Increasing intravenous doses of naloxone (0.3 mg/kg, 1 mg/kg, and 2 mg/kg) were administered to normal subjects. Naloxone at 2 mg/kg, but not at lower doses, impaired aspects of memory as measured by a verbal learning task which assessed the direct free recall and recognition of presented versus non-presented words of a single category (effortful processing) and the monitoring of the frequency of such presentations (automatic processing). At the same time "working" memory was left unaffected. The results suggest a role for the opioid system in some memory processes in man.

Adult↗
PubMed1983

The measurement of endorphins in body fluids.

The measurement of endorphins in body fluids has been an important advance in clinical research attempting to link the endogenous opioid system to psychiatric illness and symptomatology. The consideration of methodologic differences in assay technique and in clinical methods is important in evaluating results of studies. Whereas findings in early clinical studies supported the notion of increased endorphin system function in patients with schizophrenia, cumulative data from the considerable number of studies carried out throughout world centers have been unable to demonstrate a consistent abnormality in levels of endorphins in CSF or plasma of patients with schizophrenia. Among the affective disorders, data suggest the possibility of relative changes in levels of opioids within individual manic-depressive patients when studied across state change from depression to mania. In studies of depressive illness there is accumulating evidence that the endogenous opioid system may relate or contribute to abnormality of the HPA axis. In our work measuring opioids in CSF we have observed relationships between anxiety and CSF opioids in normals and psychiatric patients and changes in CSF opioid activity in patients with anorexia nervosa accompanying weight change. These data are consistent with other evidence linking endorphins to CNS noradrenergic systems and to biologic response to stress.

Anorexia Nervosa↗