Effects of 1-desamo-8-D-arginine vasopressin on behaviour and cognition in primary affective disorder

Potential clinical applications of current and future oral forms of desmopressin (Review)

Desmopressin is a synthetic analogue of vasopressin and a selective vasopressin receptor 2 agonist. It was first synthesised in 1967 and utilised for its antidiuretic properties. It is also used in bleeding disorders to enhance clotting. Other potential uses of the drug have been reported. The present review aims to provide a broad overview of the literature on potential further uses of oral forms of desmopressin. Key therapeutic areas of interest were identified based on known physiological activities/targets of desmopressin or reports of an effect of desmopressin in the literature. The feasibility of adequate dosing with oral forms of the drug was also considered. Systematic literature searches were carried out using the silvi.ai software for the identified areas, and summaries of available papers were included in tables and discussed. The results of the searches showed that desmopressin has been investigated for its efficacy in a number of areas, including bleeding control, renal colic, the central nervous system and oncology. Evidence suggests that oral desmopressin may have the potential to be of clinical benefit for renal colic and bleeding control in particular. However, further research is needed to clarify its effect in these areas, including randomised controlled studies and studies specifically of oral formulations (and doses). Further research may also yield findings for cancer, cognition and overactive bladder.

The physiological and pathophysiological functions of renal and extrarenal vasopressin V2 receptors

The arginine vasopressin (AVP) type 2 receptor (V2R) is unique among AVP receptor subtypes in signaling through cAMP. Its key function is in the kidneys, facilitating the urine concentrating mechanism through the AVP/V2 type receptor/aquaporin 2 system in the medullary and cortical collecting ducts. Recent clinical and research observations strongly support the existence of an extrarenal V2R. The clinical importance of the extrarenal V2R spans widely from stimulation of coagulation factor in the endothelium to as yet untested potential therapeutic targets. These include V2R-regulated membranous fluid turnover in the inner ear, V2R-regulated mitogensis and apoptosis in certain tumor tissues, and numerous other cell types where the physiological role of V2Rs still requires further research. Here, we review current evidence on the physiological and pathophysiological functions of renal and extrarenal V2Rs. These functions of V2R are important, not only in rare diseases with loss or gain of function of V2R but also in relation to the recent use of nonpeptide V2R antagonists to treat hyponatremia and possibly retard the growth of cysts and development of renal failure in autosomal dominant polycystic kidney disease. The main functions of V2R in principal cells of the collecting duct are water, salt, and urea transport by modifying the trafficking of aquaporin 2, epithelial Na(+) channels, and urea transporters and vasodilation and stimulation of coagulation factor properties, mainly seen with pharmacological doses of 1-desamino-8-D-AVP. The AVPR2 gene is located on the X chromosome, in a region with high probability of escape from inactivation; this may lead to phenotypic sex differences, with females expressing higher levels of transcript than males.

Lack of vasopressin does not prevent the behavioural and endocrine changes induced by chronic unpredictable stress

Vasopressin (VP) plays an important role in hypothalamo-pituitary-adrenal (HPA) axis regulation and in stress-related disorders. Our previous studies confirmed the role of VP in acute situations, where VP-deficient Brattleboro rats had less depression-like behaviour compared to animals that express VP. In this study, we test the hypothesis that VP-deficient rats are more resistant to the development of chronic HPA axis hyperactivity and depression-like symptoms after chronic unpredictable stress (CUS). Male VP-deficient Brattleboro rats were compared to their heterozygous littermates (controls). CUS consisted of different mild stimuli for 5 weeks. Elevated plus maze and forced swim test were used for behavioural characterization, while organs and blood for HPA axis parameters were collected at the end of the experiment. In controls, CUS resulted in the development of chronic stress state characterized by typical somatic (body weight reduction, thymus involution) and endocrine changes (resting plasma ACTH and corticosterone elevation and POMC mRNA elevation in anterior lobe of the pituitary). Floating time in the forced swim test was enhanced together with reduced open arm entries on elevated plus maze and a reduction in daily food intake. Unexpectedly, the lack of VP did not alter the effect of CUS on the somatic and behavioural measures, but only prevented CUS-induced corticosterone changes. In conclusion, lifelong VP-deficiency has a positive effect on corticosterone elevation following CUS but does not affect the behavioural consequences of CUS. It is likely that the interplay of several related factors, rather than an alteration in a single neuropeptide, modulates behaviour and disease pathogenesis.

Vasopressin as a target for antidepressant development: an assessment of the available evidence

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis is one of the key biological abnormalities described in major depressive disorder, occurring in 30-50% of depressed subjects. Corticotropin-releasing hormone (CRH) and vasopressin (AVP) are the main regulators of this stress system, with the two neuropeptides acting synergistically in bringing about adrenocorticotropin (ACTH) release from the anterior pituitary and cortisol from the adrenal gland. Based on the demonstration of elevated cerebrospinal fluid levels of CRH in depressives, and other evidence, it has been postulated that excess CRH and the resultant increased HPA forward drive form the basis of neuroendocrine dysregulation in depression. However, there is an accumulating body of evidence to support a significant role for AVP in the regulation of pituitary-adrenal activity in health and also in depressive disorder. This review, based on a Medline search from 1980 to 2001, focuses on the functional neuroanatomy, receptor pharmacology, VP synergism with CRH, and the data from clinical and pre-clinical studies that support an important role for AVP in the pathophysiology of major depression. We suggest that future antidepressants may target the vasopressinergic system.

Depression in schizophrenia: I. Association with neuropsychological deficits

BACKGROUND

The presence of depression in schizophrenia has been well described with regard to stage and symptoms of illness; however, little is known about the possible etiology.

METHODS

In an effort to advance the understanding of the neurobiology of depression in schizophrenia, we grouped patients with schizophrenia based on their ratings on the 21-item Hamilton Depression Rating Scale. There were 63 patients (35 men, 28 women) in the high (> or = 18) depression group and 81 patients (52 men, 29 women) in the low (< 18) depression group. The groups were compared in demographic, clinical, and eight neuropsychological domains.

RESULTS

The two groups differed in age at onset of illness, severity of delusions, and performance in a single neuropsychological domain: attention. The specific component of impaired attention was vigilance, with poorest performance seen in women with higher depression scores.

CONCLUSION

The presence of specific attentional impairment associated with depressive symptoms in schizophrenia is consistent with the hypothesis of frontal lobe dysfunction in depression, because these regions have been implicated in attentional processes.

Brain tumors in children and adolescents--III. Effects of radiation and hormone status on intelligence and on working, associative and serial-order memory

The effects on intelligence and memory of two post-surgical conditions (radiation treatment, hormone deficiency and supplementation) were explored in 46 children and adolescents with tumors in a variety of brain sites. Verbal intelligence, but not non-verbal intelligence, varied positively with age at radiation treatment. Memory for word meanings was unrelated to either radiation history or to hormone status. Severe deficits in serial position memory occurred with impaired hormone function and an older age at tumor onset. Severe deficits in working memory were associated with a history of radiation and a principal tumor site that involved thalamic/epithalamic brain regions. Radiation treatment and hormone status affect later cognitive function in children and adolescents with brain tumors. Although the greater vulnerability of the verbal intelligence of the younger radiated child and the serial order memory of the child with later tumor onset and hormone disturbances remain to be explained, and although the form of the relationship between radiation and tumor site is not fully understood, the data highlight the need to consider the cognitive consequences of pediatric brain tumors according to a set of markers that include maturational rate, hormone status, radiation history, and principal site of the tumor.

Effects of DDAVP on movement planning and execution processes in the healthy elderly

Effects of DDAVP on speed and consistency of planning and executing simple and complex movements in healthy older adults were studied. A simple reaction time (SRT) task, a single-plane movement task, and two tasks involving multiplane movements of distal upper extremities were performed with and/or without a 0.6 ml intranasal dose (60 micrograms) of DDAVP or placebo. Results indicated that DDAVP had no significant effect on speed or consistency of SRT processes, or the speed with which simple or complex movements were planned or executed. There was also no effect on retention of motor responses.

Two regimens of lithium prophylaxis and renal function

Two regimens of lithium prophylaxis with different pharmacokinetic characteristics were compared under double-blind conditions in 25 bipolar patients in remission already stabilized on lithium, to determine the relative effects of each regimen on renal function. Once-daily lithium carbonate (Priadal), which gives a peak lithium plasma level 2-3 h post-administration with a low level 24 h later, was compared with twice-daily lithium citrate (Litarex), which maintains a steadier 24 h plasma level. Patients were allocated randomly to one of the 2 regimens. They were seen monthly for clinical ratings over the course of 12 months. A comprehensive battery of renal function tests was undertaken at the start of the trial, between 6-9 months after the start and again after 1 year. No significant differences were observed in clinical outcome, side effects or renal function between the 2 regimens.

Vasopressin and vasopressin analogues for treatment of memory disorders in clinical practice

1. Beyond its antidiuretic and vasopressor effects, vasopressin has central nervous system effects, first described in rats by David de Wied in 1965. 2. Its first clinical use in humans, in 1978, confirmed its stimulant action in normal individuals, especially in middle-aged male subjects. 3. Its utility in mnemic problems is also worht considering when the pathology is relatively recent (less than 2 years prior) and unaccompanied by major neurological lesions. Behavioral modifications, such as improvement of "sociability", "mood" improvement, independent of its effects on memory have been described, and would justify complementary clinical investigation. 4. New synthetic vasopressin derivatives which would eliminate metabolic effects while maintaining behavioral effects intact, and the definition of clinical, neuroendocrine, and neurophysiological prognostic criteria, will be the two most important paths for investigation over the next years.

Inhibitory influence of oxytocin infusion on contingent negative variation and some memory tasks in normal men

A double-blind study combining electrophysiological and psychometrical approaches was carried out to investigate the central effects of an intravenous oxytocin (OT) infusion in normal men. Contingent negative variation (CNV) was selected as the measure of central cognitive evoked potential, and the psychometric tests measured mood, vigilance and memory. OT infusion induced a significant decrease of CNV amplitude and an increase of post-imperative positive potentials in vertex derivations. A similar effect was still evidenced one week after treatment in frontal derivations, suggesting a long time effect of OT on human brain. No significant influence of OT on mood or vigilance tests was apparent; only one item of a memory test revealed a significant impairment of some mnesic performances. These observations provide new electrophysiological arguments supporting a central action of peripheral OT administration in man.

Cerebrospinal fluid vasopressin--changes in depression

Cerebrospinal fluid (CSF), thyrotropin releasing hormone (TRH), CSF-vasopressin (AVP), plasma-AVP, CSF-osmolality, plasma-osmolality, CSF-adrenaline (A) and -noradrenaline (NA) were measured in psychiatric patients and controls. Psychiatric patients were classified according to ICD-9 and grouped into endogenous depression, non-endogenous depression, mania and schizophrenia. The depressive groups were classified according to the Newcastle Rating Scale for Depression 1965. Severity of disease was quantified by BRMES, BRMS and BPRS. No difference in CSF-TRH levels was seen among the different diagnostic groups and controls. A positive correlation between CSF-TRH and CSF-A was demonstrated. CSF-AVP concentrations were significantly lowered in both endogenous and non-endogenous depression; no correlation with CSF-A or -NA was seen. Neither did any difference between plasma levels of AVP, plasma-osmolality or CSF-osmolality appear among the groups investigated.

A mnemonic role for vasopressin: the evidence for and against

This review critically evaluates the animal and human research concerning vasopressin's putative mnemonic role. Weaknesses in the interpretations of the early animal experiments as well as the implications of the later inconsistent findings are discussed. It is concluded that both the initial enthusiasm and the subsequent skepticism concerning this hypothesized role were premature. This conclusion applies equally to the human research. A review of these studies reveals that almost all of the negative reports involved cognitively-impaired individuals. The relatively few studies that have been conducted concerning vasopressin's effects in unimpaired human subjects are consistent with the hypothesis that vasopressin does affect cognition, though both the mechanism of action and the specific cognitive processes which are altered have yet to be elucidated.

Neurochemical aspects of depression: the past and the future?

The role of aberrant neurochemical substrates in the etiology of depression and the neurochemical mechanisms of antidepressant therapies have been the subjects of many hypotheses in the last 30 years. Pharmacological studies of early antidepressant drugs indicated that brain monoamines were significantly affected by these drugs and these led to the formulation of the biogenic amine hypothesis of depression. Although this hypothesis has been of heuristic value in the study of drug mechanisms and has provided a basis for screening drugs for antidepressant potential, deficiencies in it have become apparent. Neuroanatomical and neurochemical considerations favour the view that brain noradrenaline and serotonin systems may serve as bias adjusting systems for each other and numerous other neural systems. As a consequence of such a relationship, a primary defect in some other neural system would appear amplified in measurements of serotonin or noradrenaline. A possible site for this primary defect may be in membrane composition and function. Recent studies have found that typical and other antidepressant therapies have a pronounced effect on membrane lipids. Thus, in view of the important functions of membrane lipids and the fact that they have been linked to the initiation and development of a number of other disease processes, it is now suggested that consideration be given to them as playing primary causal roles in the etiology of depression and as a site of action for antidepressant drugs.

Aversive effects of subcutaneously injected vasopressin in the rat: independence of the ascending dorsal noradrenergic bundle

The unconditioned stimulus properties of subcutaneously administered arginine vasopressin (AVP) were examined using place and taste conditioning paradigms. Evidence for an aversive effect of the peptide was found, in general agreement with a previous report, although a high dose of AVP (10 micrograms) was required. Also investigated was the possible role of the dorsal noradrenergic bundle (DNAB) in conditioned taste aversion established by AVP. Although the DNAB has been proposed as one of the central pathways through which AVP exerts a facilitatory effect on conditioned behaviour, destruction of this pontine-forebrain projection with 6-hydroxydopamine did not appear to alter the aversiveness of the drug in the present study. These results replicate the finding that AVP can serve as an aversive stimulus but also indicate that the aversive properties of the peptide may prove to be dissociable from its ability to enhance the retention of learned behaviour.

Desglycinamide-9-arginine-8-vasopressin (DGAVP, Organon 5667) in patients with dementia

Vasopressin peptides have been shown to facilitate learning and memory in both animals and humans; however, the effectiveness in humans is controversial. In a double blind parallel group study, 17 demented subjects (either Alzheimer's or alcoholic) were given either desglycinamide-9-arginine-8-vasopressin (DGAVP) 92 micrograms intranasally TID or an identical placebo for 1 week after having received 1 week of placebo. To our knowledge, this is the first report of DGAVP being used in subjects with dementia. The DGAVP group had a statistically significant improvement on the Buschke list learning of low imagery words. However, for various reasons discussed in the paper, we feel this finding needs to be replicated before any definite conclusions can be drawn. Since there were no other appreciable behavioral effects of this DGAVP regimen, our results should be considered negative. There was no evidence of any DGAVP-related adverse effects, except for possible weight gain.

Side-effects of lithium at lower therapeutic levels: the significance of thirst

The prevalence of thirst, subjective polyuria and related side-effects was investigated in 87 patients attending a lithium clinic and in a group of 52 controls. Thirst was surprisingly common, occurring in 67% of patients, in spite of the fact that they had been maintained on relatively low levels of lithium, and was due principally to the lithium rather than to other psychotropic drugs. Urine flow and impaired renal water absorption correlated with the serum lithium level and the length of treatment in the patients, despite the fact that few were clinically polyuric. The pattern of the results confirms previous suggestions that lithium may stimulate the thirst mechanism directly as well as via an increased renal resistance to vasopressin. The possible implications in terms of clinical response are discussed.

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.

Neuropeptides in the cerebrospinal fluid (CSF) in psychiatric disorders

Concentrations of vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK) and gastrin in the cerebrospinal fluid (CSF) was studied in patients with endogenous depression, non-endogenous depression, mania, schizophrenia and a control group. All patients were classified according to various diagnostic systems. In the group of non-endogenously depressed patients CSF-VIP levels (median 16 pmol/l) were found significantly lowered compared to controls (median = 32 pmol/l) and endogenous depression (26 pmol/l). Going through the non-endogenous group it appeared that the low CSF-VIP was due to a group of patients with a former diagnosis of endogenous depression or a present diagnosis of possible endogenous depression. Moreover, this group was clinically characterized by 'dysphoric/hysterical features', 'reversed diurnal variation' (i.e. worst in the evening), and 'lack of clearly circumscribed episode'. In many aspects this group seems similar to the atypical depressions described as monoamineoxidase responders. Concerning CSF-CCK and CSF-gastrin no significant differences between the examined groups were demonstrated.

A clinical trial with desglycinamide arginine vasopressin for the treatment of memory disorders in man

In a double-blind cross-over trial the memory effect of the neuropeptide desglycinamide arginine vasopressin (DGAVP) was selected because of its well-documented facilitatory effects on memory components in rodents. Patients with stabilized or progressive amnesic disorders (Korsakoff disease, early stages of Alzheimer dementia, head injuries and other central nervous system diseases) did not respond to the drug. Factors possibly explaining the discrepancy with animal research are discussed.

Intracerebroventricular application of a vasopressin antagonist peptide prevents the behavioral actions of vasopressin

Three experiments were conducted to test the hypothesis that the memory-improving properties of peripherally-applied vasopressin (AVP) were related to its aversive (i.e. arousing) actions. The memory effects of AVP were observed in a one-trial food-finding task where non-deprived rats were briefly exposed to a large open field that contained an alcove in which a high-incentive familiar food reward (sweetened milk) was freely available. AVP injections immediately upon removal from the open-field produced faster latencies to refind the alcove (compared to vehicle controls) when tested 48 h later. The aversive actions of AVP were demonstrated in two behavioral assays: (1) a conditioned taste aversion test in which rats learned to avoid a preferred saccharin solution after it had been paired with injections of AVP; and (2) a conditioned place test in which rats learned to avoid a distinctive environment associated with AVP administration. Both the memory and aversive responses to AVP were prevented, in a dose-dependent manner, by immediate pretreatment with intracerebroventricular infusions of the pressor antagonist analog 1-deaminopenicillamine-2-(O-methyl)-tyrosine AVP. The large antagonist doses required to block AVP's behavioral effects suggest that the critical site of action may be far removed from the lateral ventricles. The possibility that AVP-induced improvements in memory result from peripheral arousing actions is discussed.

A critique of the vasopressin-memory hypothesis

During the past 20 years, evidence has accumulated to suggest that the neuropeptide vasopressin (VP) enhances memory by acting on central mechanisms, and that oxytocin (OT) has amnestic effects. In this review, the evidence for the memory hypothesis with respect to VP is considered and alternative interpretations evaluated. A critical approach has been adopted; negative findings, design considerations and problems with the various hypotheses are given prominence. It is concluded that the memory hypothesis fails to provide an adequate account, and some alternative theories and suggestions are discussed. It is speculated that the peptide may affect behaviour by two distinct mechanisms: peripheral action may involve reinforcement mechanisms, but its central role may be to modulate arousal level, especially in stressful situations.

The effect of vasopressin on memory in the healthy elderly

The effect that vasopressin has upon memory in young and old males was tested in a double-blind crossover study. There were two 1-week medication periods; during one, subjects received 60 micrograms of vasopressin daily; during the other, placebo. Reaction time tasks were used to measure their speed of retrieval from: short-term memory (STM), long-term memory (LTM), and semantic memory (SM). While vasopressin did not affect SM retrieval time or simple vocal reaction time, it did reduce memory comparison time and perceptual-motor time in STM and retrieval time in LTM. The degree of facilitation was similar in young and old.

Human memory and neurohypophyseal hormones: opposite effects of vasopressin and oxytocin

A classical task of experimental psychology, the retention of lists of words, was given twice to three groups of subjects treated with lysine vasopressin (LVP), oxytocin or saline. From a baseline session (no treatment) to a second session with treatment, the LVP and placebo groups showed an enhancement of the number of words remembered correctly, whereas the oxytocin group did not. Rather, oxytocin impaired memory performance. However, we cannot claim a memory enhancing effect of LVP, because placebo treatment enhanced memory performance to the same extent.

Centrally mediated effects of neurohypophyseal hormones

The neurohypophyseal hormones oxytocin and vasopressin cause a variety of biological effects in animals which are mediated by central nervous system mechanisms. Among the best studied of these effects is the modulation of both memory processes and the development of drug tolerance and dependence. Neurohypophyseal hormones have also been shown to alter various physiological parameters such as heart rate and body temperature following central administration. In addition, these peptides can profoundly alter spontaneous, unlearned behavior in several rodent species. Many of the centrally mediated effects of neurohypophyseal hormones have been shown to be elicited at sites within the brain stem and the limbic system where vasopressin and oxytocin occur in cell bodies, axons and nerve terminals, suggesting a physiological role for these peptide effects. The various central effects of neurohypophyseal hormones involve different mechanisms which can be distinguished from one another on the basis of required dose, time-course of action, and structure-activity relationships. Thus, alterations of spontaneous behavior are mediated by putative receptors closely related to vasopressin receptors in blood vessels responsible for the peripheral pressor response while the effects on memory processes are mediated by a mechanism which is not closely related to those involved in the peripheral hormonal effects of the peptides. The influence of neurohypophyseal hormones on memory and attention may be useful clinically. A potential role for these peptides in mental disorders is discussed.

Abnormalities in plasma and cerebrospinal-fluid arginine vasopressin in patients with anorexia nervosa

Previous studies have indicated that many patients with anorexia nervosa have defects in urinary concentration or dilution suggestive of abnormal secretion of the antidiuretic hormone arginine vasopressin. To explore this possibility, we examined the response of plasma vasopressin to intravenous hypertonic saline in anorexic patients before and after correction of their weight loss. We also measured basal levels of the hormone in the cerebrospinal fluid. In all four subjects studied before correction of weight loss, the response to hypertonic saline was abnormal: in one, the plasma level of arginine vasopressin increased subnormally relative to the plasma sodium level; in the other three, it fluctuated erratically, with no relation to plasma sodium. These defects persisted in the three patients studied three to four weeks after recovery of body weight. In two patients who were initially studied when they were underweight, the defects were gone six months after recovery; in five of seven other patients studied at least six months after recovery but not while they were underweight, the response was normal. Abnormalities in the osmoregulation of plasma arginine vasopressin were not accounted for by nonosmotic stimuli and were almost always associated with an absolute increase in the level of arginine vasopressin in the cerebrospinal fluid or a reversal of the normal (less than 1.0) cerebrospinal fluid/plasma ratio of arginine vasopressin. These results indicate that most if not all patients with anorexia nervosa have abnormal levels of arginine vasopressin in their plasma and cerebrospinal fluid that are corrected very slowly with weight gain. The cause and consequences of these abnormalities remain to be determined.

Vasopressin potentiation in the performance of a learned appetitive task: reversal by a pressor antagonist analog of vasopressin

Rats were tested in a simple one-trial water-finding task for the effects of arginine vasopressin (AVP) on performance of an appetitive task. On the training day, each animal was exposed for 5 min to a novel open-field environment that contained a water-tube located in an alcove set into one of the walls of the enclosure. Immediately upon removal from the enclosure, the animals received a subcutaneous injection of either AVP (1 microgram/rat) or vehicle solution. When water-deprived and tested 48 hr later, vasopressin-treated rats found the water tube reliably faster than controls. In other groups of animals, this potentiation in learned performance was prevented by concurrently treating the rats with a vasopressin analog having potent pressor antagonist properties. These results are consistent with the notion that vasopressin may play a role in memory consolidation, but peripheral visceral factors may mediate this action.

Effects of DDAVP, a vasopressin analog, on delayed matching behavior in the pigeon

Five pigeons were tested in a delayed matching-to-sample task after receiving an acute injection of DDAVP (1-desamino-8-D-arginine), scopolamine or d-amphetamine. A feeding test also was used to document non-specific drug effects. Scopolamine produced a marked dose-related decrement in accuracy of matching, regardless of delay, indicating that scopolamine impairs both discrimination and short-term memory. Neither DDAVP nor d-amphetamine produced consistent changes in delayed matching. Thus, an experimental model of short-term memory with pigeons did not confirm the findings of others of a positive effect of DDAVP upon cognitive performance in humans.

Effect of desmopressin on normal and impaired memory

In view of the reported influence of vasopressin on the memory process of animals, trials were carried out on normal subjects and patients with memory disorders using the vasopressin analogue desmopressin. No beneficial effects could be demonstrated.

Peptides in the cerebrospinal fluid of neuropsychiatric patients: an approach to central nervous system peptide function

This review highlights that essentially all of the recently discovered putative central nervous system (CNS) peptides and other peptide substances are measurable in human cerebrospinal fluid (CSF). Preliminary evidence also suggests that peptides in CSF may have an active regulatory role in relation to CNS function and behavior. Even if this is not the case, CSF peptides may prove to be a useful indirect marker of CNS peptide function and metabolism. Alterations in peptides have been reported in neurological and psychiatric illness, pain symptoms and their treatment, symptoms such as anxiety, and following treatment with CNS active drugs such as carbamazepine. CSF methodologies provide a strategy for the study of the interaction of classical neurotransmitters and peptide substances and their relationship to neural function and behavior in man. Assessment of peptides in CSF may supplement post mortem studies of peptide levels and receptor distribution and help lead to new diagnostic and treatment approaches in neuropsychiatric disorders.

Effects of vasopressin on memory and new learning in a brain-injured population

Vasopressin was administered in the form of a nasal spray to a group of 7 head-injured patients and compared with placebo in its effects on intellectual functioning, each patient serving as his own control. No significant differences in performance were found during the conditions of placebo and the active agent.