Chronic social defeat up-regulates expression of norepinephrine transporter in rat brains

Stress has been reported to activate the locus coeruleus (LC)-noradrenergic system. However, the molecular link between chronic stress and noradrenergic neurons remains to be elucidated. In the present study adult Fischer 344 rats were subjected to a regimen of chronic social defeat (CSD) for 4weeks. Measurements by in situ hybridization and Western blotting showed that CSD significantly increased mRNA and protein levels of the norepinephrine transporter (NET) in the LC region and NET protein levels in the hippocampus, frontal cortex and amygdala. CSD-induced increases in NET expression were abolished by adrenalectomy or treatment with corticosteroid receptor antagonists, suggesting the involvement of corticosterone and corticosteroid receptors in this upregulation. Furthermore, protein levels of protein kinase A (PKA), protein kinase C (PKC), and phosphorylated cAMP-response element binding (pCREB) protein were significantly reduced in the LC and its terminal regions by the CSD paradigm. Similarly, these reduced protein levels caused by CSD were prevented by adrenalectomy. However, effects of corticosteroid receptor antagonists on CSD-induced down-regulation of PKA, PKC, and pCREB proteins were not consistent. While mifeprestone and spironolactone, either alone or in combination, totally abrogate CSD effects on these protein levels of PKA, PKC and pCREB in the LC and those in the hippocampus, frontal cortex and amygdala, their effects on PKA and PKC in the hippocampus, frontal cortex and amygdala were region-dependent. The present findings indicate a correlation between chronic stress and activation of the noradrenergic system. This correlation and CSD-induced alteration in signal transduction molecules may account for their critical effects on the development of symptoms of major depression.

Differential regulation of the serotonin 1 A transcriptional modulators five prime repressor element under dual repression-1 and nuclear-deformed epidermal autoregulatory factor by chronic stress

Chronic stress is known to affect brain areas involved in learning and emotional responses. These changes, thought to be related to the development of cognitive deficits are evident in major depressive disorder and other stress-related pathophysiologies. The serotonin-related transcription factors (Freud-1/CC2D1A; five prime repressor element under dual repression/coiled-coil C2 domain 1a, and NUDR/Deaf-1; nuclear-deformed epidermal autoregulatory factor) are two important regulators of the 5-HT1A receptor. Using Western blotting and quantitative real-time polymerase chain reaction (qPCR) we examined the expression of mRNA and proteins for Freud-1, NUDR, and the 5-HT1A receptor in the prefrontal cortex (PFC) of male rats exposed to chronic restraint stress (CRS; 6 h/day for 21 days). After 21 days of CRS, significant reductions in both Freud-1 mRNA and protein were observed in the PFC (36.8% and 32%, respectively; P<0.001), while the levels of both NUDR protein and mRNA did not change significantly. Consistent with reduced Freud-1 protein, 5-HT1A receptor mRNA levels were equally upregulated in the PFC, while protein levels actually declined, suggesting post-transcriptional receptor downregulation. The data suggest that CRS produces distinct alterations in the serotonin system specifically altering Freud-1 and the 5-HT1A receptor in the PFC of the male rat while having no effect on NUDR. These results point to the importance of understanding the mechanism for the differential regulation of Freud-1 and NUDR in the PFC as a basis for understanding the related effects of chronic stress on the serotonin system (serotonin-related transcription factors) and stress-related disorders like depression.

Repeated immobilization stress alters rat hippocampal and prefrontal cortical morphology in parallel with endogenous agmatine and arginine decarboxylase levels

Agmatine, an endogenous amine derived from decarboxylation of L-arginine catalyzed by arginine decarboxylase, has been proposed as a neurotransmitter or neuromodulator in the brain. In the present study, we examined whether agmatine has neuroprotective effects against repeated immobilization-induced morphological changes in brain tissues and possible effects of immobilization stress on endogenous agmatine levels and arginine decarboxylase expression in rat brains. Sprague-Dawley rats were subjected to 2h immobilization stress daily for 7 days. This paradigm significantly increased plasma corticosterone levels, and the glutamate efflux in the hippocampus as measured by in vivo microdialysis. Immunohistochemical staining with beta-tubulin III showed that repeated immobilization caused marked morphological alterations in the hippocampus and medial prefrontal cortex that were prevented by simultaneous treatment with agmatine (50mg/kg/day), i.p.). Likewise, endogenous agmatine levels measured by high-performance liquid chromatography in the prefrontal cortex, hippocampus, striatum and hypothalamus were significantly increased by immobilization, as compared to controls. The increased endogenous agmatine levels, ranging from 92 to 265% of controls, were accompanied by a significant increase of arginine decarboxylase protein levels in the same regions. These results demonstrate that the administration of exogenous agmatine protects the hippocampus and medial prefrontal cortex against neuronal insults caused by repeated immobilization. The parallel increase in endogenous brain agmatine and arginine decarboxylase protein levels triggered by repeated immobilization indicates that the endogenous agmatine system may play an important role in adaptation to stress as a potential neuronal self-protection mechanism.

Rapid eye movement sleep deprivation decreases long-term potentiation stability and affects some glutamatergic signaling proteins during hippocampal development

Development of the mammalian CNS requires formation and stabilization of neuronal circuits and synaptic connections. Sensory stimulation provided by the environment orchestrates neuronal circuit formation in the waking state. Endogenous sources of activation are also implicated in these processes. Accordingly we hypothesized that sleep, especially rapid eye movement sleep (REMS), the stage characterized by high neuronal activity that is more prominent in development than adulthood, provides endogenous stimulation, which, like sensory input, helps to stabilize and refine neuronal circuits during CNS development. Young (Y: postnatal day (PN) 16) and adolescent (A: PN44) rats were rapid eye movement sleep-deprived (REMSD) by gentle cage-shaking for only 4 h on 3 consecutive days (total 12 h). The effect of REMS deprivation in Y and A rats was tested 3-7 days after the last deprivation session (Y, PN21-25; A, PN49-53) and was compared with younger (immature, I, PN9-12) untreated, age-matched, treated and normal control groups. REMS deprivation negatively affected the stability of long-term potentiation (LTP) in Y but not A animals. LTP instability in Y-REMSD animals was similar to the instability in even the more immature, untreated animals. Utilizing immunoblots, we identified changes in molecular components of glutamatergic synapses known to participate in mechanisms of synaptic refinement and plasticity. Overall, N-methyl-d-aspartate receptor subunit 2B (NR2B), N-methyl-d-aspartate receptor subunit 2A, AMPA receptor subunit 1 (GluR1), postsynaptic density protein 95 (PSD-95), and calcium/calmodulin kinase II tended to be lower in Y REMSD animals (NR2B, GluR1 and PSD-95 were significantly lower) compared with controls, an effect not present in the A animals. Taken together, these data indicate that early-life REMS deprivation reduces stability of hippocampal neuronal circuits, possibly by hindering expression of mature glutamatergic synaptic components. The findings support a role for REMS in the maturation of hippocampal neuronal circuits.

Neuroprotective effects of agmatine against cell damage caused by glucocorticoids in cultured rat hippocampal neurons

In the present study the neuroprotective effects of agmatine against neuronal damage caused by glucocorticoids were examined in cultured rat hippocampal neurons. Spectrophotometric measurements of lactate dehydrogenase activities, beta-tubulin III immunocytochemical staining, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick-end-labeling assay (TUNEL) labeling and caspase-3 assays were carried out to detect cell damage or possible involved mechanisms. Our results show that dexamethasone and corticosterone produced a concentration-dependent increase of lactate dehydrogenase release in 12-day hippocampal cultures. Addition of 100 microM agmatine into media prevented the glucocorticoid-induced increase of lactate dehydrogenase release, an effect also shared with the specific N-methyl-D-aspartate receptor antagonist MK801 and glucocorticoid receptor antagonists mifepristone and spironolactone. Arcaine, an analog of agmatine with similar structure as agmatine, also blocked glucocorticoid-induced increase of lactate dehydrogenase release. Spermine and putrescine, the endogenous polyamine and metabolic products of agmatine without the guanidino moiety of agmatine, have no appreciable effect on glucocorticoid-induced injuries, indicating a structural relevance for this neuroprotection. Immunocytochemical staining with beta-tubulin III confirmed the substantial neuronal injuries caused by glucocorticoids and the neuroprotective effects of agmatine against these neuronal injuries. TUNEL labeling demonstrated that agmatine significantly reduced TUNEL-positive cell numbers induced by exposure of cultured neurons to dexamethasone. Moreover, exposure of hippocampal neurons to dexamethasone significantly increased caspase-3 activity, which was inhibited by co-treatment with agmatine. Taken together, these results demonstrate that agmatine can protect cultured hippocampal neurons from glucocorticoid-induced neurotoxicity, through a possible blockade of the N-methyl-D-aspartate receptor channels or a potential anti-apoptotic property.

Rapid eye movement sleep deprivation in post-critical period, adolescent rats alters the balance between inhibitory and excitatory mechanisms in visual cortex

Suppression of rapid eye movement sleep (REMS) in developing animals has both anatomical and physiological consequences. We have recently shown that initiating REMS deprivation (REMSD) prior to the end of the critical period in young rats delays termination of the critical period (CP) in visual cortex, and, consequently, the synaptic plasticity mechanisms that support a developmentally regulated form of long-term potentiation (LTP) are maintained in an immature state [J.P. Shaffery, C.M. Sinton, G. Bisset, H.P. Roffwarg, G.A. Marks, Rapid eye movement sleep deprivation modifies expression of long-term potentiation in visual cortex of immature rats, Neuroscience, 110 (2002) 431-443]. In CP animals, high-frequency, theta burst stimulation (TBS) directed at the white matter (WM) below visual cortex produces LTP in the post-synaptic cells in layer II/III (LTPWM-III). However, LTPWM-III can be induced in cortical tissue taken from REMS-deprived animals for up to a week beyond the usual end of the CP [J.P. Shaffery, C.M. Sinton, G. Bisset, H.P. Roffwarg, G.A. Marks, Rapid eye movement sleep deprivation modifies expression of long-term potentiation in visual cortex of immature rats, Neuroscience, 110 (2002) 431-443]. Further, in post-CP, adolescent animals (as late as postnatal day 60), REMSD appears to unmask synaptic plasticity mechanisms that allow for production of developmentally regulated LTPWM-III [J.P. Shaffery, J. Lopez, G. Bissette, H.P. Roffwarg, Rapid eye movement sleep deprivation revives a form of developmentally regulated synaptic plasticity in the visual cortex of post-critical period rats, Neurosci Lett., (2005), in press]. It has been proposed that REMSD's effects on production of LTPWM-III result from a reduction in efficiency of the inhibitory mechanisms thought to precipitate termination of the CP of brain development [J.P. Shaffery, J. Lopez, G. Bissette, H.P. Roffwarg, Rapid eye movement sleep deprivation revives a form of developmentally regulated synaptic plasticity in the visual cortex of post-critical period rats, Neurosci Lett., (2005), in press]. In this study we tested the hypothesis that low-frequency stimulation (LFS) of the fibers of the WM, which usually produces the related form of synaptic plasticity, long-term depression (LTD), will also reflect the reduction in inhibitory tone. We report here that LFS protocols, which in normally sleeping, adolescent rats usually produce either LTD or no change in response magnitude, in REMS-deprived, adolescent rats are more likely to produce LTP.

Rapid eye movement sleep deprivation revives a form of developmentally regulated synaptic plasticity in the visual cortex of post-critical period rats

The critical period for observing a developmentally regulated form of synaptic plasticity in the visual cortex of young rats normally ends at about postnatal day 30. This developmentally regulated form of in vitro long-term potentiation (LTP) can be reliably induced in layers II-III by aiming high frequency, theta burst stimulation (TBS) at the white matter situated directly below visual cortex (LTPWM-III). Previous work has demonstrated that suppression of sensory activation of visual cortex, achieved by rearing young rats in total darkness from birth, delays termination of the critical period for inducing LTPWM-III. Subsequent data also demonstrated that when rapid eye movement sleep (REMS) is suppressed, thereby reducing REMS cortical activation, just prior to the end of the critical period, termination of this developmental phase is delayed, and LTPWM-III can still be reliably produced in the usual post-critical period. Here, we report that for approximately 3 weeks immediately following the usual end of the critical period, suppression of REMS disrupts the maturational processes that close the critical period, and LTPWM-III is readily induced in brain slices taken from these somewhat older animals. Insofar as in vitro LTP is a model for the cellular and molecular changes that underlie developmental synaptic plasticity, these results suggest that mechanisms of synaptic plasticity, which participate in brain development and perhaps also in learning and memory processes, remain susceptible to the effects of REMS deprivation during the general period of adolescence in the rat.

Omega-3 status and cerebrospinal fluid corticotrophin releasing hormone in perpetrators of domestic violence

BACKGROUND

Elevated levels of corticotrophin-releasing hormone in the cortical-hippocampal-amygdala pathway increase fear and anxiety, which are components of defensive and violent behaviors. Prostaglandins E2 and F2alpha, which increase corticotrophin-releasing hormone RNA expression in this pathway, are reduced by dietary intakes of omega-3 fats.

METHODS

Among 21 perpetrators of domestic violence, cerebrospinal fluid and plasma were assessed for corticotrophin-releasing hormone and fatty acid compositions, respectively.

RESULTS

Lower plasma docosahexaenoic acid (wt% fatty acids) alone predicted greater cerebrospinal fluid corticotrophin-releasing hormone (pg/mL), in exponential (r = -.67, p < .006) and linear regressions (r = -0.68, p < .003 excluding four subjects with the highest docosahexaenate levels).

CONCLUSIONS

In this small observational study, low plasma docosahexaenoic acid levels were correlated to higher cerebrospinal fluid corticotrophin-releasing hormone levels. Placebo controlled trials can determine if dietary omega-3 fatty acids can reduce excessive corticotrophin-releasing hormone levels in psychiatric illnesses.

Corticotropin-releasing factor in posttraumatic stress disorder (PTSD) with secondary psychotic symptoms, nonpsychotic PTSD, and healthy control subjects

BACKGROUND

Recent studies have reported a high comorbidity between posttraumatic stress disorder (PTSD) and psychotic symptoms, and it has been hypothesized that PTSD with comorbid psychosis is a severe form of PTSD. Few studies have examined the neurobiology of PTSD with comorbid psychosis. If PTSD with secondary psychotic symptoms (PTSD-SP) is a severe form of PTSD, then it might be expected to show more extreme perturbations in the neuroendocrine patterns that characterize PTSD.

METHODS

Patients with PTSD with secondary psychotic symptoms (PTSD-SP), PTSD without psychosis, and healthy comparison subjects were compared for differences in cerebrospinal fluid concentrations of corticotropin-releasing factor (CRF) and somatotropin-release-inhibiting hormone (SRIF).

RESULTS

The PTSD-SP subjects had significantly higher mean levels of CRF than either the PTSD or control subjects (p <.01). The three groups showed similar SRIF levels.

CONCLUSIONS

These data implicate abnormalities in the secretion of CRF with the production of secondary psychotic symptoms in PTSD. This finding supports the validity of PTSD-SP as a PTSD subtype and as a severe form of PTSD.

Elevated concentrations of CRF in the locus coeruleus of depressed subjects

Research evidence that corticotropin-releasing factor (CRF) plays a role in the pathophysiology of major depressive disorder (MDD) has accumulated over the past 20 years. The elevation of lumbar cerebrospinal fluid (CSF) concentrations of CRF decreased responsiveness of pituitary CRF receptors to challenge with synthetic CRF, and increased levels of serum cortisol in MDD subjects support the hypothesis that CRF is chronically hypersecreted in at least the endocrine circuits of the hypothalamic-pituitary-adrenal (HPA) axis and may also involve other CRF brain circuits mediating emotional responses and/or arousal. One such circuit includes the excitatory CRF input to the locus coeruleus (LC), the major source of norepinephrine in the brain. Furthermore, there are now reports of decreased levels of CRF in lumbar CSF from MDD patients after symptom relief from chronic treatment with antidepressant drugs or electroconvulsive therapy. Whether this normalization reflects therapeutic effects on both endocrine- and limbic-associated CRF circuits has not yet been effectively addressed. In this brief report, we describe increased concentrations of CRF-like immunoreactivity in micropunches of post-mortem LC from subjects with MDD symptoms as established by retrospective psychiatric diagnosis compared to nondepressed subjects matched for age and sex.

CSF CRH in abstinent cocaine-dependent patients

Alterations in stress responsivity may be important in the vulnerability to become cocaine dependent. Thus, an index of hypothalamic-pituitary-adrenal (HPA) axis function was examined in abstinent cocaine-dependent patients. Cerebrospinal fluid (CSF) concentrations of corticotropin releasing factor (CRH) were determined in 29 abstinent cocaine-dependent patients and 66 normal controls. The results showed that there was no significant difference between the abstinent cocaine-dependent patients and normal controls for CSF CRH. Also, CSF CRH concentrations were not related to cocaine-craving scores in a cue-elicited cocaine-craving procedure. Thus, these data suggest that after protracted abstinence from cocaine there is no marked dysregulation of CRH systems as measured by CSF CRH concentrations.

Relationship between cortisol and serotonin metabolites and transporters in alcoholism [correction of alcolholism]

BACKGROUND

Stress hormone activation may induce clinical depression via an interference with central serotonergic neurotransmission. In alcoholics, a reduction in serotonin transporters was associated with clinical depression, and an activation of cortisol secretion is frequently found during detoxification. We assessed the interaction between stress hormone activation, serotonin transporters, monoamine metabolites in the cerebrospinal fluid (CSF), and mood states in male and female alcoholics and healthy control subjects.

METHODS

The availability of serotonin transporters was measured with [I-123]beta-CIT and SPECT in the raphe area of the brainstem in 31 alcoholics after four weeks of abstinence and in 25 age-matched healthy volunteers. Concentrations of plasma cortisol were measured on the day of the SPECT scan. Within one week after the SPECT scan, we assessed monoamine metabolites and corticotropin-releasing factor (CRF) in the CSF.

RESULTS

Clinical depression was associated with a reduction in serotonin transporter availability among male alcoholics. Among male alcoholics and healthy volunteers, CSF 5-HIAA and plasma cortisol concentrations were inversely correlated with the availability of raphe serotonin transporters and positively correlated with the severity of clinical depression. No significant correlations were observed between raphe serotonin transporters and HVA, MHPG and CRF concentrations in the CSF.

CONCLUSION

Our findings support the hypothesis of an interaction between reduced serotonin transporters, stress hormone activation and clinical depression. They confirm the hypothesis that serotonergic neurotransmission dysfunction in alcoholism is limited to male alcoholics. The observed interactions between high cortisol concentrations and reduced serotonin transporter availability warrant further studies in major depression and other neuropsychiatric diseases with implied cortisol activation and serotonergic dysfunction.

Rapid eye movement sleep deprivation modifies expression of long-term potentiation in visual cortex of immature rats

During rapid eye movement (REM) sleep, activity of non-retinal origin is propagated into central visual-system pathways in a manner similar, in pattern and intensity, to central visual-system activity that is exogenously generated in waking. It has been hypothesized that REM sleep, which is more abundantly represented early in life than later, functions to provide adjunct 'afferent' input for shaping synaptic connectivity during brain maturation. Here we present data that support this proposal. Recent studies have described a developmentally regulated form of in vitro long-term potentiation (LTP) in the visual cortex that is experience- and age-dependent. In immature rats, suppression of retinal activation of the visual system by removal of visual experience (dark rearing) extends the age when the developmentally regulated form of LTP can be produced. This study tests whether suppression of REM-state activation of the visual system also lengthens the developmental period in which this specific form of LTP can be elicited. Young rats were deprived of REM sleep by the multiple-small-platforms-over-water method during the typically latest week for induction of such LTP in slices of visual cortex. After this week, we could still induce LTP in slices from nearly all the REM-sleep-deprived rats (8/9) but not from age-matched rats that had not lost REM sleep (0/5). The control rats had been housed on large platforms that allow the animals to obtain REM sleep. Only body weights and the concentration of thyrotrophin-releasing hormone in the hypothalamus distinguished home-caged, normal-sleeping controls from both groups of platform animals. On all measures, stress levels were not dissimilar in the two platforms groups. After 7 days of behavioral suppression of REM sleep in immature rats, and consequent reduction of the intense, extra-retinal activity endogenously generated during this sleep state, we found that the period was extended in which developmentally regulated synaptic plasticity (LTP) could be elicited in slices of visual neocortex. These studies support the role of REM sleep and its associated neuronal activity in brain maturation.

CSF thyrotropin-releasing hormone concentrations differ in patients with schizoaffective disorder from patients with schizophrenia or mood disorders

OBJECTIVE

To determine if there were differences in CSF-TRH concentrations among several acute major psychiatric disorders and to investigate the effects of antipsychotic treatment on CSF-TRH levels.

METHOD

CSF-TRH concentrations were measured in 62 psychiatric inpatients during an acute phase of illness after a drug-free period. CSF-TRH measurements were repeated in 14 of these patients after 4 weeks of antipsychotic treatment.

RESULTS

Post-hoc tests (Tukey HSD) revealed significant differences among patients with schizoaffective disorder and both schizophrenia (P<0.03) and major depression (P<0.01). There were no significant differences between pre and posttreatment levels of CSF-TRH in the 14 patients treated with conventional agents for 4 weeks (1.54 pg/ml vs. 1.47 pg/ml). However, patients with a reduction in CSF-TRH concentration had a significantly better symptom response measured by the Brief Psychiatric Rating Scale (BPRS) positive factor (61% in six subjects) vs. those who had an increase in posttreatment CSF-TRH (29% in eight subjects; t=2.2; d.f.=12; P<0.04).

CONCLUSIONS

These results provide further evidence for a neuromodulatory role for TRH and suggest a re-examination of its behavioral effects and interactions with brain neurotransmitter systems relevant to major psychotic and mood disorders.

Effects of sertraline on regional neuropeptide concentrations in olfactory bulbectomized rats

Corticotropin-releasing factor (CRF) and thyrotropin-releasing hormone (TRH) are two neuropeptides that exhibit increased cerebrospinal fluid (CSF) concentrations during major depressive episodes while somatostatin (somatotropin-release inhibiting factor, SRIF) is decreased. Clinical and basic research findings indicate that clinically effective antidepressant therapies often normalize the indicators of CRF and TRH hypersecretion as well as SRIF hyposecretion. The olfactory bulbectomized (OBX) rat is used to screen potential antidepressant drugs for clinical efficacy. This model requires chronic administration of the antidepressant drug to normalize OBX-induced behaviors such as increased locomotion in a novel environment. This report describes the regional brain concentration changes in CRF, TRH and SRIF produced by OBX and demonstrates the ability of the selective serotonin re-uptake inhibitor and antidepressant drug, sertraline (10 mg/kg), to normalize certain of these alterations in regional neuropeptide concentrations as well as normalizing OBX-induced increases in locomotor activity. OBX-induced increases in CRF concentrations in the hypothalamus and bed nucleus of the stria terminalis were specifically and significantly decreased by sertraline. OBX-induced increases in TRH concentrations in the hypothalamus were reversed by sertraline. The concentration of SRIF was significantly reduced by OBX in the anterior caudate and the piriform cortex, but sertraline reversed these changes only in the anterior caudate.

Neuropeptides in CSF and post-mortem brain tissue of normal controls, schizophrenics and Huntington's choreics

Studies describing the CNS distribution of neuropeptides can provide important new insights concerning their possible physiological functions. The rational for studying human post-mortem tissue, as well as some methodological constraints, are reviewed. The localization of NT in normal human brain is presented. Concentrations of NT, TRH, and SRIF were determined in brain tissue from normal controls and patients with schizophrenia or Huntington's chorea. Specific alterations in the levels of these neuropeptides were found in each disease. Appreciable quantities of NT immunoreactivity are present in human CSF. Sub-normal CSF-NT levels were found in a sub-group of unmedicated schizophrenics but were elevated back to normal concentrations following neuroleptic treatment. Although the pathophysiological significance of these findings is unclear, they nevertheless indicate that neuropeptides are important brain constituents which deserve further study.

Neurotensin-like immunoreactivity in cerebrospinal fluid of patients with schizophrenia, depression, anorexia nervosa-bulimia, and premenstrual syndrome

Neurotensin (NT) concentrations in cerebrospinal fluid (CSF) were measured by a sensitive and specific radioimmunoassay in psychiatric patients and age- and sex-matched normal controls. No increase in CSF NT concentrations was observed after antipsychotic drug treatment. CSF NT concentrations were significantly lower in one group of schizophrenic subjects. NT concentrations were unaltered in patients with depression, anorexia/bulimia, or premenstrual syndrome, and no rostral-caudal gradient for NT in CSF was evident. NT concentrations were not related to age or sex, and probenecid treatment did not alter CSF NT concentrations. Finally CSF NT concentrations were unaltered in paranoid schizophrenic subjects. These findings confirm and extend previous studies of CSF NT that showed certain patients with schizophrenia, nonparanoid type, have reduced CSF concentrations of this tridecapeptide.

Cerebrospinal fluid concentrations of corticotropin-releasing hormone, vasopressin, and somatostatin in depressed patients and healthy controls: response to amitriptyline treatment

The effect of amitriptyline upon hypothalamic-pituitary-adrenal [HPA]-system-regulating neuropeptides (corticotropin-releasing hormone [CRH], vasopressin, somatostatin) was studied in a group of depressed elderly patients and controls. A first lumbar puncture was performed in 37 depressed in-patients. This was followed by a 6-week medication phase with amitriptyline. Upon its completion a second cerebrospinal fluid (CSF) sample was obtained in 18 of these 37 patients. In 25 healthy controls a first lumbar puncture was done eleven of these individuals agreed to take 75 mg/d amitriptyline for 6 weeks and to participate in the follow-up CSF study. Within the group of depressed patients amitriptyline led to a significant decrease of CSF CRH in treatment responders only (F1, 16 = 5.2; P < 0.02). Also, in normal controls CSF CRH concentration tended to decrease with amitriptyline treatment (t-test; P < 0.09). No effects of amitriptyline upon vasopressin or somatostatin were observed. In normal controls (r = 0.4; P < 0.02) and in patients (r = 0.4; P < 0.03) age correlated positively with baseline CSF somatostatin. A trend for CSF CRH to increase with aging was found only in controls (r = 0.3; P < 0.09); patients did not show a significant association here. Finally, CSF neuropeptide concentration at baseline did not differ between the group of depressed patients and healthy controls. Our study corroborates the evolving concept that antidepressants effect various components of the HPA system with the net result of a reduction in its activity. In addition, we found CSF CRH and CSF somatostatin concentrations to be better reflections of age than of depression and, finally, that during aging and during depression the HPA system changes in similar directions.

Modeling geriatric depression in animals: biochemical and behavioral effects of olfactory bulbectomy in young versus aged rats

Geriatric depression exhibits biological and therapeutic differences relative to early-onset depression. We studied olfactory bulbectomy (OBX), a paradigm that shares major features of human depression, in young versus aged rats to determine mechanisms underlying these differences. Young OBX rats showed locomotor hyperactivity and a loss of passive avoidance and tactile startle. In contrast, aged OBX animals maintained avoidance and startle responses but showed greater locomotor stimulation; the aged group also exhibited decreased grooming and suppressed feeding with novel presentation of chocolate milk, effects which were not seen in young OBX. These behavioral contrasts were accompanied by greater atrophy of the frontal/parietal cortex and midbrain in aged OBX. Serotonin transporter sites were increased in the cortex and hippocampus of young OBX rats, but were decreased in the aged OBX group. Cell signaling cascades also showed age-dependent effects, with increased adenylyl cyclase responses to monoaminergic stimulation in young OBX but no change or a decrease in aged OBX. These data indicate that there are biological distinctions in effects of OBX in young and aged animals, which, if present in geriatric depression, provide a mechanistic basis for differences in biological markers and drug responses. OBX may provide a useful animal model with which to test therapeutic interventions for geriatric depression.

Regional Neuropeptide Pathology in Alzheimer's Disease: Corticotropin-Releasing Factor and Somatostatin

BACKGROUND: the neuropeptides most consistently reported to be altered in Alzheimer's disease are corticotropin-releasing factor and somatostatin (somatotropin-release inhibiting factor), although this has been previously assessed in a limited number of brain regions. METHODS: in order to comprehensively characterize the involvement of these two anatomically distinct neuropeptide systems in Alzheimer's disease and to determine if they are equally involved in the associated pathology, we measured the concentration of corticotropin-releasing factor and somatostatin in post-mortem brain tissue. Radioimmunoassay of 24 cortical and 13 sub-cortical brain regions from 16 cases of neuropathologically confirmed AD and 9 non-Alzheimer's disease controls were performed and significant differences in group regional neuropeptide concentrations were sought using the Student Newman-Keuls test after ANOVA. RESULTS: comparison of group mean regional neuropeptide concentrations revealed several brain regions where both peptides were decreased in Alzheimer's disease and some regions where only one of the two peptides were decreased, while still other regions exhibited no changes in either peptide. These changes were principally found in frontal and temporal cortex, with few subcortical regions exhibiting pathologic changes in peptide concentration. Regional peptide content was correlated among peptides and with duration of dementia in several brain regions. CONCLUSIONS: these data support the hypothesis that the somatostatin- and corticotropin-releasing factor containing neurons are pathologically involved in AD and that the involved neurons are limited to specific areas of the brain.

CSF neurotensin concentrations and antipsychotic treatment in schizophrenia and schizoaffective disorder

OBJECTIVE

The relationship between CSF neurotensin concentrations and measures of psychopathology in patients with schizophrenia or schizoaffective disorder was examined before and after treatment with antipsychotic drugs.

METHOD

CSF neurotensin concentrations were measured in 42 drug-free patients with schizophrenia or schizoaffective disorder. For 18 of these patients, CSF neurotensin was measure again after 4 weeks of antipsychotic treatment.

RESULTS

Significantly higher levels of pretreatment psychopathology were observed in the patients with the lowest CSF neurotensin concentrations. Furthermore, improvements in overall psychopathology and, particularly, negative symptoms were correlated with increases in CSF neurotensin concentrations during treatment.

CONCLUSIONS

These findings provide further evidence for a role of neurotensin the pathophysiology of psychosis and in the mechanism of action of antipsychotic drugs.

Cerebrospinal fluid concentrations of corticotropin-releasing hormone (CRH) and diazepam-binding inhibitor (DBI) during alcohol withdrawal and abstinence

The neuropeptides diazepam binding inhibitor (DBI) and corticotropin-releasing hormone (CRH) elicit anxietylike symptoms when administered intracerebroventricularly to laboratory animals. Because of the similarities between the symptoms of certain anxiety states and the alcohol withdrawal syndrome, we hypothesized that increased secretion of either of these endogenous neuropeptides may, at least in part, be responsible for the symptoms of alcohol withdrawal. We therefore measured DBI and CRH concentrations in cerebrospinal fluid (CSF) of 15 alcohol-dependent patients during acute withdrawal (Day 1) and again at 3 week's abstinence (Day 21). In addition, plasma concentrations of cortisol were measured to evaluate the relationship between pituitary-adrenal axis activation and CSF CRH concentrations. CSF CRH (p < .04), but not CSF DBI, was significantly higher on Day 1 than on Day 21. Although there was a significant decrease in plasma cortisol from Day 1 to Day 21 (p < .001), a significant correlation between CSF CRH and plasma cortisol concentrations was not observed at either time point. Neither CSF neuropeptide correlated with clinical measures of withdrawal severity. These tentative findings may implicate CRH, but not DBI, in the pathogenesis of alcohol withdrawal. Alternately, the central release of CRH and DBI may not be adequately reflected in lumbar CSF.

Elevated cerebrospinal fluid corticotropin-releasing factor in Tourette's syndrome: comparison to obsessive compulsive disorder and normal controls

Stress- and anxiety-related fluctuations in tic severity are cardinal features of Tourette's syndrome (TS), and there is evidence for involvement of noradrenergic mechanisms in the pathophysiology and treatment of the disorder. To examine further the pathobiology of this enhanced vulnerability to stress and anxiety, we measured central activity of corticotropin-releasing factor (CRF) in patients with TS and the related condition, obsessive compulsive disorder (OCD). Lumbar cerebrospinal fluid (CSF) was obtained in a standardized fashion for measurement of CRF from 21 medication-free outpatients with TS, 20 with OCD, and 29 healthy controls. The TS patients had significantly higher levels of CSF CRF than both the normal controls and the OCD patients. However, there was no difference in CSF CRF between the OCD patients and the normal controls. Group differences in CSF CRF were unrelated to current clinical ratings of depression, anxiety, tics, and obsessive compulsive behaviors. Although the functional significance of this finding remains to be elucidated, these results are consistent with the hypothesis that stress-related neurobiological mechanisms may play a role in the pathobiology of TS.

Cerebrospinal fluid corticotropin-releasing factor concentrations in patients with anxiety disorders and normal comparison subjects

Cerebrospinal fluid (CSF) concentrations of corticotropin-releasing factor (CRF) were measured in a group of patients with anxiety disorders and normal comparison subjects (NC) to explore the hypothesis that abnormalities in CRF neuronal regulation occur in patients with anxiety disorders. Analysis of variance (ANOVA) revealed no differences in CSF CRF concentrations between the four diagnostic categories: panic disorder (PD), generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), and NCs. Male OCD patients had higher CSF CRF concentrations than men with PD and GAD and male NCs. CSF CRF concentration was positively correlated with age in women but not in men. These findings suggest that central neuronal CRF regulation may be affected by both age and gender.

High affinity choline transporter status in Alzheimer's disease tissue from rapid autopsy

The degeneration of nucleus basalis cholinergic neurons in Alzheimers disease (AD) has led to therapies that attempt to increase the synaptic availability of acetylcholine in the remaining cholinergic nerve terminals and to thereby reverse or slow the progressive dementia accompanying the disease process. The inadequacy of current choline-replacement therapies suggests that utilization of choline may be disordered and the rate-limiting step in acetylcholine synthesis, the high affinity choline transporter, may be involved. An adequate test of this hypothesis requires the use of fresh, unfrozen tissue, as the transporter activity declines rapidly after death. Using tissue acquired within two hours of death, the activity of the high affinity choline transporter was shown to be increased in cortical brain regions from AD patients compared to non-AD controls. Further studies using frozen tissues with similar short postmortem acquisition times, revealed the expression of the high affinity uptake transporter to be increased in AD cortex as well. When the ratio of regional uptake activity or expression to the regional level of choline acetyltransferase was calculated, the increase in choline transporter activity and expression was clearly statistically significant. Further statistical significance in the choline transporter activity of the AD group was achieved when the putamen, a region without marked pathology in AD, was used as an internal standard to control for agonal state differences in the individual patients contributing tissue to this study. These increases in choline transporter expression and activity in AD indicate disordered regulation of this rate-limiting component of acetylcholine synthesis above and beyond that required to compensate for the reduced cholinergic synaptic availability in AD.

Elevation of CSF somatostatin concentrations in mania

OBJECTIVE

The aim of this study was to compare levels of CSF somatostatin (somatotropin release-inhibiting factor) in drug-free patients with different major psychiatric disorders.

METHOD

CSF somatostatin concentrations were measured in 66 drug-free inpatients with Research Diagnostic Criteria diagnoses of schizophrenia, major depressive disorder, manic disorder, or schizoaffective disorder.

RESULTS

In comparison with both the patients with schizophrenia and the patients with schizoaffective disorder, the manic patients had markedly elevated CSF somatostatin concentrations. The depressed patients had significantly higher levels than the schizophrenic patients.

CONCLUSIONS

Mania is associated with relatively higher CSF somatostatin concentrations.

Apparent seasonal rhythms in hypothalamic neuropeptides in rats without photoperiod changes

An apparent seasonal or circannual rhythm in the hypothalamic content of CRF, TRH, neurotensin, and neuromedin N has been observed in 12 separate monthly coherts (n = 10@ or 130 total) adult, male Sprague-Dawley rats obtained at the same time each month from a single commercial supplier and held under constant (12:12) photoperiod conditions since birth. Both annual and 4-month (terannual) harmonics can be statistically discerned in these apparent rhythms, which exhibit cycles containing concentration changes up to 3-fold the lowest levels across the year (CRF increases 390%, TRH increases 173%, neurotensin increases 136%, and neuromedin N increases 150%). Hypothalamic somatostatin did not exhibit these statistically significant robust rhythms nor did any peptide in regions outside the hypothalamus. These data indicate that a mechanism allowing enhanced or diminished physiological availability of these regulatory neuropeptides at different times of the year may exist and may display distinct cycles even in the absence of normal photoperiod cues. Possible regulatory responses of pituitary receptor populations for these hypothalamic peptides must be considered. As certain of these neuropeptides also appear to be altered in the cerebrospinal fluid of patients with major depression or schizophrenia, similar hypothalamic cyclic changes may underly psychiatric symptoms with seasonal periodicity.

Neurochemical correlates of sympathetic activation during severe alcohol withdrawal

Cerebrospinal fluid (CSF) was obtained from 17 patients during acute alcohol withdrawal. Eight of these 17 patients had a second lumbar puncture a mean of 11.9 +/- 8.1 (SD) days later, when the clinical signs of alcohol withdrawal had subsided. CSF 3-methoxy-4-hydroxyphenylglycol concentrations declined significantly (p < 0.05) during the course of alcohol withdrawal from 52.0 +/- 22.1 (SD) to 39.6 +/- 12.6 pM/ml. In early withdrawal, there was a significant positive correlation between CSF norepinephrine (NE) and corticotropin releasing hormone (CRH) concentrations (r = 0.95, p < 0.001). Both NE and CRH concentrations correlated positively with diastolic blood pressure (r = 0.88, p < 0.001 and r = 0.62, p < 0.05, respectively). In all samples, CSF 5-hydroxyindole acetic acid concentrations correlated positively with CSF-homovanillic acid concentrations (r = 0.83, p < 0.001). These findings indicate significant perturbations of the noradrenergic neuronal system and a change in CRH-NE interactions during acute alcohol withdrawal.

Cerebrospinal fluid somatostatin concentrations in schizophrenia and schizoaffective disorder: the effects of antipsychotic treatment

The authors examined the effects of antipsychotic treatment on cerebrospinal fluid somatostatin like immunoreactivity (CSF SLI) in 14 schizophrenic and 3 schizoaffective patients. There was a modest but significant increase in CSF SLI in 13 out of the 14 schizophrenic patients. In addition, there was a significant positive correlation between duration of treatment and post-treatment CSF SLI concentrations. No differential response was noted in patients also treated with the anticholinergic benztropine.

Effects of haloperidol, quinelorane, and lithium on regional neurotensin/neuromedin N concentrations: further evidence for neurotensin/neuromedin N-dopamine interactions

In order to further characterize the pharmacologic mechanisms that mediate the antipsychotic drug-induced increase in neurotensin (NT) in nucleus accumbens and striatum, the effects of three weeks treatment with psychotherapeutic levels of lithium alone or in conjunction with haloperidol were compared to the ability of haloperidol alone to alter NT and neuromedin N (NMN) regional brain concentrations in rats. A separate experiment examined the ability of a selective dopamine D2 receptor agonist, quinelorane, to alter NT/NMN regional concentrations after three weeks of treatment as compared to haloperidol, a D2 receptor antagonist. Haloperidol (1 mg/kg) increased both NT and NMN concentrations in several brain regions and these parallel peptide increases were highly correlated. Lithium chloride (0.4 mM) had no effect, either alone or with haloperidol, on NT/NMN concentrations. Quinelorane (1 mg/kg), however, effectively increased both NT and NMN concentrations in the caudate nucleus and nucleus accumbens, as did haloperidol (2 mg/kg). These data indicate that the induction of NT and NMN, whose adjacent sequences are contained in a pro-hormone product of a single gene, occurs in tandem and remains proportional, as well as demonstrating that putative D2 receptor agonists can produce effects on NT/NMN systems that are similar to D2 receptor antagonists.

Carbamazepine increases cerebrospinal fluid thyrotropin-releasing hormone levels in affectively ill patients

BACKGROUND

Thyrotropin-releasing hormone is an endogenous tripeptide with endocrine-independent neurophysiologic properties that may be relevant to affective or seizure disorders. We studied the effect of carbamazepine, which has both mood-stabilizing and anticonvulsant properties, on cerebrospinal fluid thyrotropin-releasing hormone levels in affectively ill patients.

METHOD

Paired cerebrospinal fluid samples were collected from nine inpatients with mood disorders, both while medication free and while taking carbamazepine for an average of longer than 1 month at 950 mg/d, achieving blood levels of 8.8 mg/L.

RESULTS

Carbamazepine treatment was consistently and significantly associated with increased cerebrospinal fluid thyrotropin-releasing hormone levels (P < .0001).

CONCLUSION

As carbamazepine-induced increases in thyrotropin-releasing hormone levels could be relevant to either its psychotropic or anticonvulsant properties, further clinical and preclinical investigation of this finding appears indicated.

Overexpression of the high affinity choline transporter in cortical regions affected by Alzheimer's disease. Evidence from rapid autopsy studies

Cholinergic deficits in Alzheimer's disease are typically assessed by choline acetyltransferase, the enzyme that synthesizes acetylcholine. However, the determining step in acetylcholine formation is choline uptake via a high affinity transporter in nerve terminal membranes. Evaluating uptake is difficult because regulatory changes in transporter function decay rapidly postmortem. To overcome this problem, brain regions from patients with or without Alzheimer's disease were frozen within 4 h of death and examined for both choline acetyltransferase activity and for binding of [3H]-hemicholinium-3 to the choline transporter. Consistent with the loss of cholinergic projections, cerebral cortical areas exhibited marked decreases in enzyme activity whereas the putamen, a region not involved in Alzheimer's disease, was unaffected. However, [3H]hemicholinium-3 binding was significantly enhanced in the cortical regions. In the frontal cortex, the increase in [3H]hemicholinium-3 binding far exceeded the loss of choline acetyltransferase, indicating transporter overexpression beyond that necessary to offset loss of synaptic terminals. These results suggest that, in Alzheimer's disease, the loss of cholinergic function is not dictated simply by destruction of nerve terminals, but rather involves additional alterations in choline utilization; interventions aimed at increasing the activity of cholinergic neurons may thus accelerate neurodegeneration.

CSF concentrations of neurotensin in schizophrenia: an investigation of clinical and biochemical correlates

Neurotensin (NT), a peptide which colocalizes with dopamine in some midbrain and hypothalamic neurons, has been speculated to play a role in schizophrenic illness and in the action of antipsychotic drugs. Previous work suggested a bimodal distribution of NT in patients with schizophrenia, with a subgroup having low drug-free NT concentrations which normalize with neuroleptic treatment. We studied 15 schizophrenic patients with CSF samples collected both off and on neuroleptic medication, 12 with only drug-free (DF) samples, and 10 controls. There was no significant difference in CSF NT concentrations between patients and controls, or between patients off and on medication. However, 7 patients with DFNT CSF concentrations below the patient mean showed an increase with neuroleptic treatment. Moreover, NT was significantly lower for women. Significant correlations with NT concentrations in CSF were found with deficit symptoms in patients, and with the age of the CSF sample for all subjects. There was no correlation between CSF NT concentrations and patient age, duration of illness, or levels of amine metabolites (MHPG, 5HIAA, HVA).

Differences in CSF concentrations of thyrotropin-releasing hormone in depressed patients and normal subjects: negative findings

Since there have been reports of elevated CSF concentrations of thyrotropin-releasing hormone (TRH) in depression, the authors compared the TRH levels of 17 depressed patients and 19 normal subjects. All subjects underwent lumbar punctures after fasting overnight, and CSF concentrations of TRH were determined by radioimmunoassay. CSF concentrations of norepinephrine and monoamine metabolites were also measured. There was no significant difference between the two groups on any measure, and in the depressed patients there was no significant relation between CSF concentrations of TRH and thyrotropin-stimulating hormone responses to TRH infusion.

Cerebrospinal fluid corticotropin-releasing factor increases following haloperidol withdrawal in chronic schizophrenia

Corticotropin-releasing factor (CRF), an endogenous neuropeptide, has been shown to coordinate endocrine, behavioral and autonomic responses to stress. However, while previous studies of cerebrospinal fluid (CSF) CRF in schizophrenia have not demonstrated significant differences compared to control groups, these studies have not examined the effects of symptom severity or antipsychotic medication. CSF CRF concentrations increased in 18 of 21 male schizophrenic (DSM-III-R) patients after maintenance haloperidol was replaced by placebo (P < 0.0001); there was also a trend for relatively greater increases in relapsers. CRF concentrations were not significantly related to severity of psychosis, depression, anxiety or negative symptoms. During haloperidol treatment, but not after medication withdrawal, worse childhood premorbid adjustment was associated with higher CSF CRF levels. Finally, in contrast to the positive correlation between CSF CRF and norepinephrine concentrations reported in depression, a negative trend was seen in this schizophrenic sample.

CSF biochemistries, glucose metabolism, and diurnal activity rhythms in alcoholic, violent offenders, fire setters, and healthy volunteers

BACKGROUND

There is an extensive literature describing a central serotonin deficit in alcoholic, impulsive, violent offenders and fire setters. In the present study, we investigated biochemical concomitants of impulsivity and aggressiveness, and the physiological consequences of reduced central serotonin turnover.

METHODS

Forty-three impulsive and 15 nonimpulsive alcoholic offenders and 21 healthy volunteers were studied in the forensic psychiatry ward of a university psychiatric department. The subjects underwent lumbar punctures and oral glucose and aspartame challenges, and their diurnal activity rhythm was measured with physical activity monitors. Discriminant function analyses were used to investigate psychophysiological and biochemical concomitants of aggressive and impulsive behaviors.

RESULTS

Alcoholic, impulsive offenders with antisocial personality disorder had low mean cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and corticotropin levels and high mean CSF testosterone concentrations. Compared with healthy volunteers, they showed increased physical activity during the daytime. Alcoholic, impulsive offenders with intermittent explosive disorder had a low mean CSF 5-HIAA concentration and blood glucose nadir after an oral glucose challenge, and desynchronized diurnal activity rhythm. Healthy volunteers had mean CSF 5-HIAA concentrations that were intermediate between those of alcoholic, impulsive and nonimpulsive offenders. Alcoholic, nonimpulsive offenders had a significantly higher mean CSF 5-HIAA concentration than all the other groups, including healthy volunteers.

CONCLUSIONS

In the present sample, a low CSF 5-HIAA concentration was primarily associated with impulsivity and high CSF testosterone concentration, with aggressiveness or interpersonal violence.

Cerebrospinal fluid TRH immunoreactivity in anorexia nervosa

Central nervous system (CNS) thyrotropin-releasing hormone (TRH) activity is of interest in patients with anorexia nervosa. First, anorexics have peripheral thyroid abnormalities that appear to be related to weight and nutritional status. Second, CNS TRH activity may effect many other physiologic systems that are known to be disturbed in patients with anorexia nervosa. We found that anorexic patients, when both underweight and studied after attaining goal weight, had significantly reduced CSF TRH concentrations in comparison to controls. These data suggest that weight gain or increased caloric intake, in contrast to its large effect on peripheral thyroid function, has relatively little effect on CNS TRH activity. The reason for reduced CSF TRH in goal weight anorexics is not known but could be trait related, a persistent defect slow to normalize after weight gain, or related to these patients still being at a weight lower than controls. Finally, in terms of CSF TRH concentrations, this study suggests that anorexia nervosa has a different pathophysiology than major depressive disorder.

Personality profiles and state aggressiveness in Finnish alcoholic, violent offenders, fire setters, and healthy volunteers

BACKGROUND

Based on clinical observations in a series of studies on Finnish alcoholic, violent offenders, we asserted that the impulsive offenders represented an extreme group of type 2 alcoholics. We also observed that these subjects were vulnerable to hypoglycemia after the administration of oral glucose load. Furthermore, we believe that while being hypoglycemic, the impulsive offenders are particularly irritable and aggressive. In the present study, we addressed these issues by studying psychological trait and state variables in a new group of violent offenders and fire setters, and age- and sex-matched healthy volunteers.

METHODS

Fifty-eight alcoholic, violent offenders and impulsive fire setters and 21 healthy volunteers were administered the Karolinska scales of personality and the Rosenzweig picture frustration test after an oral aspartame and glucose challenge.

RESULTS

The psychological test results and the criminal histories of the offenders, together with biochemical measurements, suggest that a low 5-hydroxyindoleacetic acid concentration in cerebrospinal fluid in the alcoholic offenders is associated with irritability and impaired impulse control, and a high free testosterone concentration in cerebrospinal fluid is associated with increased aggressiveness, monotony avoidance, sensation seeking, suspiciousness, and reduced socialization.

CONCLUSION

Finnish alcoholic, impulsive offenders have personality profiles characteristic of Scandinavian early-onset male alcoholics with antisocial traits, who have been also referred to as type 2 alcoholics.

Alzheimer's-disease-related protein in geriatric schizophrenic patients with cognitive impairment

The authors compared Alz-50 immunoreactivity in the brain tissue of nine cognitively impaired elderly schizophrenic patients and 13 elderly comparison subjects, both without neuritic plaques or neurofibrillary tangles, and 13 patients with Alzheimer's disease. Alz-50 reactivity was absent in the schizophrenic patients, indicating that geriatric, cognitively impaired patients are unlikely to display the pathology of Alzheimer's disease.

Neurochemical alterations in Rett syndrome

The Rett syndrome (RS) is a neurological disorder associated with severe mental deficiency and neurological manifestations of cortical and extrapyramidal dysfunction. The present report is (1) a postmortem brain study that compares the levels of choline acetyltransferase (ChAT) activity and the binding density of selected neurotransmitter receptors in four cases of RS and five normal controls of similar age and (2) a study of cerebrospinal fluid (CSF) concentrations of the endogenous tridecapeptide neurotensin in 12 RS patients and 8 controls of similar age. The level of ChAT activity was lower in many cortical and subcortical regions in the RS brains as compared to control levels. The number of NMDA, AMPA, mu opioid and neurotensin binding sites, as well as CSF concentrations of neurotensin, did not differ significantly from control levels. The results suggest that changes in specific neurotransmitter systems, particularly cholinergic neurons, in the thalamus, cerebellum and basal ganglia may underlie the progressive deterioration in motor and cognitive function characteristic of this disorder.

Effect of desipramine on cerebrospinal fluid concentrations of corticotropin-releasing factor in human subjects

To assess the effect of desipramine (DMI) on corticotropin-releasing-factor (CRF) activity in the central nervous system, we measured cerebrospinal fluid (CSF) concentrations of CRF in healthy volunteers following short-term administration of DMI or placebo. DMI administration for 2 days was associated with a significant dose-related reduction in CRF concentrations. There was a nonsignificant 6% reduction in CRF concentrations among the 10 subjects who received 50 mg DMI (delta CRF: -3 +/- 2 pg/ml) and a significant 14% fall in the CRF concentrations of the eight subjects who received 100 mg DMI (delta CRF: -8 +/- 3 pg/ml). The mean CSF concentration of CRF was unchanged in the six subjects randomized to placebo (delta CRF: 1 +/- 5 pg/ml). DMI administration had no effect on CSF norepinephrine concentrations (n = 24) or on plasma cortisol (n = 25). We conclude that short-term administration of DMI in healthy volunteers is associated with a dose-related reduction in CSF concentrations of CRF.

CSF somatostatin in Alzheimer's disease and major depression: relationship to hypothalamic-pituitary-adrenal axis and clinical measures

Patients with Alzheimer's disease (AD) and major depression have been shown to have overlapping clinical symptoms and biological markers, including decreased concentrations of cerebrospinal fluid (CSF) somatostatin-like immunoreactivity (SLI), which may be related to alterations in the hypothalamic-pituitary-adrenal axis activity. As in prior studies, we found that CSF SLI was significantly decreased in a group of AD patients (N = 49) and a group of elderly patients with major depression (N = 18), as compared with 13 age-matched controls (F[2, 77] = 12.9, p < .001). In the present study, CSF SLI and CSF corticotropin-releasing factor correlated significantly within the group of AD patients (r = 0.49, p < .0004) and almost attained significance in the depressed patients (r = 0.47, p < .07). CSF SLI correlated significantly with urinary free cortisol within each patient group (r = -0.51, p < .03). Clinical measures of dementia severity and depression did not consistently correlate with CSF SLI in either patient group.