The present study was designed to test whether human auditory brain-stem responses (ABRs) are sensitive to peripheral endocrine signals as reflected by changes in the plasma glucocorticoid concentration. ABRs were recorded following treatment with 50 mg hydrocortisone or placebo in 13 healthy male adults. Experiments were double-blind and designed according to a latin-square within-subject comparison. Treatment was applied 1 h prior to testing as an i.v. infusion over a period of 20 min. Subjects were tested in each session under 3 X 3 conditions, i.e., ABRs were obtained to series of clicks presented at 3 different intensities (80, 60, 40 dB HL) and with 3 different stimulus rates (39, 10, 5 clicks/sec). Additionally, oral temperature was monitored. Hydrocortisone significantly reduced latencies of waves III, V, and VI (and subsequent negative troughs) when low stimulus intensities were used. Furthermore, the glucocorticoid reduced latencies of waves Vn, VI and VIn when the clicks were presented at a slow stimulus rate. Further studies have to specify the underlying mechanisms of these changes.

Adult↗

PubMedDate not supplied

Elevated plasma cortisol levels during interferon-gamma treatment.

We investigated plasma levels of cortisol and ACTH in 9 patients with advanced metastatic tumors before and during treatment with interferon-gamma (IFN-gamma), 2-4 h after administration of IFN-gamma there was a sharp rise in plasma cortisol levels. The rise coincided with the onset of fever. Highest cortisol levels were reached 4-6 h after IFN-gamma injections, whereas IFN-gamma serum levels peaked 6-10 h after the IFN-gamma injections. Elevated cortisol levels during IFN-gamma treatment may be part of a homeostatic response of the neuroendocrine system to the immunological stimulus induced by IFN-gamma. On the other hand, the increased plasma levels of cortisol in response to pharmacological doses of IFN-gamma may dampen the in vivo effectiveness of IFN-gamma.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Vasopressin does not enhance memory processes: a study in human twins.

Behavioral effects of lysin-vasopressin (LVP) were investigated applying two paradigms from human experimental psychology. The first task was designed to simulate amnesic symptoms in normals. The second task addressed the emotional value of the items to be processed. Additionally, EEG recordings were used as indicators of the central nervous system effectiveness of LVP. Blood pressure and heart rate measured peripheral arousal. The co-twin control method was employed to increase experimental power. Contrary to the prediction of the vasopressin memory hypothesis none of the specific memory parameters was improved by LVP treatment. Changes in the electrical activity of the brain, but not in blood pressure and heart rate indicated central nervous system actions of LVP. However, interpretation of LVP effects in terms of memory processing seems not to be justified.

Adolescent↗

PubMedDate not supplied

Vasopressin and electrophysiological signs of attention in man.

Seventeen pairs of monozygotic twins, females and males, were tested in a dichotic listening task, containing several types of pips: standard and deviating target pips, which the subject either attended to, or not. Averaged auditory evoked potentials (AEPs) to the pips provided measures of different attentional processes. Furthermore, EEG power spectra, heart rate and blood pressure and behavioral performance were measured. Subjects received treatments (20 I.U. lysine-vasopressin vs. placebo) intranasally 48, 24, and 1 hour prior to the experimental sessions according to a co-twin control design. Whereas measures of voluntary selective attention remained unchanged by lysine-vasopressin (LVP) the peptide primarily affected an attentional mechanism responding in an automatic fashion to stimulus deviance. This effect was indicated by a substantial negative shift of the AEP amplitudes following deviating stimuli within the latency range of the N2/P2 components (about 200 msec post-stimulus). The effect seemed to be unrelated to modulations of cortical arousal after LVP.

Adolescent↗

PubMedDate not supplied

Effects of DGAVP on verbal memory.

Effects of DGAVP (desglycinamide-arginine-vasopressin, a synthetic vasopressin analog) on verbal memory were investigated in 13 healthy male volunteers. Ten word lists, each consisting of 15 words, were presented to the subjects who had to recall them according to a free recall paradigm. The total number of recalled words was not different between DGAVP and placebo treatment; but DGAVP had an effect on memory performance depending on the serial position of the words. It attenuated the primacy effect and enhanced the recency effect of memory performance. The pattern of changes after DGAVP may be consistent with an effect of the peptide on general arousal. Since the experiment was not designed to test influences of DGAVP on arousal, these considerations remain tentative.

Adult↗

PubMedDate not supplied

Vasopressin and oxytocin do not influence early sensory processing but affect mood and activation in man.

Effects of arginine-vasopressin (AVP) and oxytocin (OX) on brainstem and middle latency auditory-evoked potentials (BAEP and MAEP), reflecting early sensory processing within the specific auditory pathways and primary auditory cortex, were investigated. Additionally, subjects rated their feelings of activation and mood on an adjective check list (EWL). The experiments were undertaken in 12 healthy male volunteers, receiving either placebo, 0.15 IU AVP, 0.5 IU AVP or 0.5 IU OX as IV bolus injection according to a within-subject double-blind design. There were no consistent effects of AVP and OX on BAEPs and MAEPs. AVP decreased self-perceived deactivation, fatigue and arousal. Results do not suggest an effect of AVP and OX on early stages of sensory processing, but, consistent with previous studies, demonstrate changes towards increased (self-perceived) general activation following administration of these hormones.

Adult↗