Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To ascertain whether Huntington's chorea and schizophrenia are associated with specific regional alterations in neurotensin, somatostatin, and thyrotropin-releasing hormone, the concentrations of these putative neurotransmitters were measured by radioimmunoassay in postmortem brain samples from patients with Huntington's chorea or schizophrenia. Compared to 50 patients without psychiatric or neurological disease, the patients with Huntington's chorea showed significantly elevated concentrations of all three neuropeptides in the nucleus caudatus. In the nucleus accumbens somatostatin levels were increased threefold, while in the amygdala thyrotropin-releasing hormone levels were elevated. In contrast, the schizophrenics exhibited reduced levels of thyrotropin-releasing hormone in two frontal cortical regions, reduced somatostatin levels in one frontal cortical area, and increased neurotensin levels in one frontal cortical area. None of the differences between the diseased brains and the controls could be accounted for by differences in age, sex, or time between death and autopsy.
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PMID:Regional brain concentrations of neuropeptides in Huntington's chorea and schizophrenia. 613 92

In Huntington's disease, there is a decrease of the neuropeptides, substance P, enkephalins, and cholecystokinin in the striatonigral system, whereas in Parkinson's disease an increase of substance P is found in the substantia nigra. Several neuropeptides should be involved in Alzheimer's disease: substance P, endorphins, vasopressin, ACTH, somatostatin, vasoactive intestinal peptide, cholecystokinin, neurotensin, delta sleep-inducing peptide. Alterations of substance P, vasoactive intestinal peptide, cholecystokinin, somatostatin, and endorphins may be related to the pathophysiology of schizophrenia. Delta sleep-inducing peptide may interfere in addiction pathology.
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PMID:Putative peptide neurotransmitters in human neuropathology: a review of topography and clinical implications. 618 57

The human brain contains several peptides with probable synaptic actions, some of which form complex neuronal networks in the limbic lobe (amygdala, hippocampus and temporal cortex). A limbic lobe abnormality has been postulated in schizophrenia on the basis of similarities between schizophrenic symptoms and symptoms in cases of known limbic pathology. Cholecystokinin (CCK), somatostatin (SRIF), neurotensin (NT), vasoactive intestinal polypeptide (VIP) and substance P (SP)-like immunoreactivities were measured by radioimmunoassay in 10 brain areas of 14 schizophrenics and 12 controls. In the schizophrenic group symptoms had been rated in life and the group was divided into Type I (n = 7) and Type II (n = 7) subgroups on the basis of the absence or presence of morbid negative symptoms. In control brains each peptide showed a characteristic distribution with high levels in cortex (CCK), limbic lobe (SOM, NT, VIP) or striatal areas (SP) and low levels of each of the peptides in thalamus. Significant (P less than 0.05) differences between groups were: reductions of CCK and SOM in hippocampus and CCK in amygdala in Type II schizophrenics, and CCK in the temporal cortex of the total schizophrenic group; and elevations of VIP in amygdala in Type I schizophrenics and of SP in the hippocampus in the total schizophrenic group. The findings could not be explained by variables such as age, delay between death and necropsy or to neuroleptic medication. These clinical-state related alterations in the peptide content of the limbic system in schizophrenia may illuminate the pathophysiological basis of the disease, particularly the distinction between Type I and II syndromes.
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PMID:Peptides, the limbic lobe and schizophrenia. 619 24

The levels of neurotensin and thyrotropin-releasing hormone (TRH) in normal post mortem human amygdala have been compared with those in cases of schizophrenia, Alzheimer's disease and depression. Amongst various factors which can influence post mortem human brain biochemistry (including age, sex, post mortem delay, time of death, disease status and severity), sex difference appeared to be responsible for the most extensive variation. The levels of both peptides were nearly doubled in males compared with females and this increase was significant in the case of neurotensin. There was also a positive correlation between neurotensin and TRH levels. Although levels of neurotensin and TRH tended to be lower in the disease groups these trends did not reach significance.
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PMID:Post mortem levels of thyrotropin-releasing hormone and neurotensin in the amygdala in Alzheimer's disease, schizophrenia and depression. 640 15

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).
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PMID:CSF concentrations of neurotensin in schizophrenia: an investigation of clinical and biochemical correlates. 751 75

Several lines of anatomical, neurochemical, electrophysiological, and behavioral evidence suggest the existence of physiological interactions between neurotensin (NT) and the brain dopaminergic systems. Thus, NT has been shown to exert a neuroleptic-like action and could be implicated in the pathogenesis and treatment of schizophrenia. It is thus of particular importance to develop in vitro cell culture systems as models to study such interactions. Rat adrenal pheochromocytoma PC12 cells, which expressed high levels of tyrosine hydroxylase, were used in the present study. In contrast to rat brain cells in primary cultures, PC12 cells did not express functional NT receptors. However, they were able to express both NTmRNA and NT in response to NGF, forskolin, and dexamethasone. Those neurochemical modifications furthermore may be related to changes in the morphology of the PC12 cells in response to NGF, forskolin, and dexamethasone alone or in combination. These data suggest that PC12 cells may provide a useful model to study in vitro the regulation of both catecholamine and neurotensin phenotypes.
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PMID:Treatment of PC12 cells by nerve growth factor, dexamethasone, and forskolin. Effects on cell morphology and expression of neurotensin and tyrosine hydroxylase. 757 2

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.
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PMID:Apparent seasonal rhythms in hypothalamic neuropeptides in rats without photoperiod changes. 783 96

Neurotensin (NT) has been proposed to be an endogenous neuroleptic based on observations that i.c.v. administration of this peptide antagonizes dopamine-mediated behavior. Because NT influences dopamine activity, this peptide may contribute to the pathogenesis of psychotic disorders such as schizophrenia; however, the precise physiological effects of NT remain speculative. In order to elucidate the function of endogenous NT, a selective NT antiserum (NTAS) was administered i.c.v. through a push-pull cannula in unanesthetized, freely moving rats in combination with dopamine activation caused by methamphetamine (METH). Locomotor and rearing activities induced by a low dose of METH (0.5 mg/kg) were substantially enhanced (4-5-fold) in rats receiving NTAS compared to control animals receiving METH alone. Similarly raised antiserum to vasoactive intestinal polypeptide (VIP) did not alter METH-induced effects. To determine a possible mechanism for these observations, perfusate delivered into the cerebral ventricular space was collected by push-pull cannulae and assayed for dopamine release. METH-induced dopamine release was enhanced 4-5-fold by co-administration of NTAS but not VIP antiserum. To verify these observations, and to identify the site of dopamine release, this experiment was repeated utilizing microdialysis and the recently described NT antagonist, SR-48692. Results from this experiment were similar to those found using NTAS. Like NTAS, co-administration of the NT antagonist enhanced the behavioral responses to a low dose of METH. These studies with SR-48692 also revealed that blockade of NT receptors increased METH-induced release of dopamine from the nucleus accumbens. These findings are the first to demonstrate directly that endogenous NT antagonizes stimulated dopamine pathways and its inactivation substantially enhances METH-induced DA release and related behaviors.
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PMID:Endogenous neurotensin antagonizes methamphetamine-enhanced dopaminergic activity. 789 59

Several lines of evidence, including the effect of antipsychotic drugs on neurotensin-containing neurons, have implicated the neurotensin system in the mechanism of action of antipsychotic drugs. Thus far, all clinically efficacious antipsychotics have been found to increase neurotensin concentrations in the nucleus accumbens; "typical" antipsychotic drugs increase neurotensin concentrations in both the nucleus accumbens and the caudate nucleus, whereas "atypical" antipsychotics increase neurotensin concentrations only in the nucleus accumbens. The effects of antipsychotic drugs on neurotensin-containing neurons in the nucleus accumbens may be predictive of clinical antipsychotic efficacy whereas the effects on neurotensin in the caudate nucleus may be predictive of extrapyramidal side effects. In addition to this evidence that antipsychotic drugs may act at least in part on neurotensin-containing neurons to produce their clinical effects is a considerable data base indicating that there are alterations in neurotensin-containing neurons in schizophrenia.
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PMID:The effects of typical and atypical antipsychotic drugs on neurotensin-containing neurons in the central nervous system. 796 68

Neurochemical investigation has played a major role in the search for the cause of schizophrenia. Initial research strategies involved the direct measurement of neurochemical substances in biological fluids. Subsequently, indirect measures of brain biochemistry including pituitary hormones and responses to pharmacologic probes were examined. Recent advances in in vivo functional neuroimaging, biochemical neuropathology, and molecular genetics have extended the scope of clinical neurochemical studies. The historical emphasis on the dopamine neurotransmitter system has subsided in the wake of the demonstrated limitations of the dopamine hypothesis of schizophrenia and increased evidence for the role of other neurotransmitters in the pathophysiology of schizophrenia as well as their interactions with dopamine neural systems. The neurotransmitters that have come under increasing scrutiny include serotonin, norepinephrine, glutamate, and related excitatory amino acids, and the neuropeptides cholecystokinin and neurotensin. In this article, the authors reviewed significant recently published neurochemical and neuroendocrine studies of schizophrenia in the context of previous work and found an extensive but fragmentary body of data which provides neither consistent nor conclusive evidence for any specific etiologic theory. Aspects of the disease and methodological limitations that may account for this as well as future research strategies are discussed.
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PMID:Neurochemistry and neuroendocrinology of schizophrenia: a selective review. 810 Jun 44


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