Determination of soluble tumor necrosis factor receptor II and secretory immunoglobulin A in saliva of patients with dementia.

The prevalence of pain and dementia increases with age, affecting a significant percentage of the population due to aging. Both pathologies are connected through the inflammatory process, specifically through the tumor necrosis factor. The effect of this cytokine is mediated through the modulation of its TNFRI and TNFRII receptors, which are linked to the dementia process. In addition, immunoglobulins such as secretory immunoglobulin A (sIgA) have been recognized as one of the main biomarkers of pain in saliva. sTNFRII and sIgA levels were determined in saliva samples by ELISA from healthy people and patients with dementia in GDS stages 5-7. The concentrations of these markers were also correlated with the GDS stage and sex. We observed a significant decrease (*** p ≤ 0.001) in the levels of sTNFRII (pg/mL) and a significant increase (** p ≤ 0.01) in the levels of sIgA (ng/mL) in the saliva of patients with dementia compared to the healthy control group. We did not observe a correlation with the data of the biomarkers regarding the GDS stage and sex. The results obtained for sTNFRII are consistent with those obtained by other authors on brain tissue, who conclude that unopposed neuronal TNFRI signaling, when TNFRII is selectively downregulated, leads to a more severe course of AD pathogenesis. Regarding sIgA, the elevated values of sIgA may reflect the immune status of these patients. Therefore, these biomarkers can provide us with relevant information through a non-invasive method such as saliva analysis.

Gender differences in the antioxidant response of oral administration of hydroxytyrosol and oleuropein against N-ethyl-N-nitrosourea (ENU)-induced glioma.

Brain tumorigenesis has been associated not only with oxidative stress, but also with a reduced response of non-enzyme and enzyme antioxidant defense systems. In fact, the imbalance between free-radical production and the efficiency of the antioxidant defense systems triggers the process because the central nervous system (CNS) is very sensitive to free-radical damage. Phenolic compounds, mainly oleuropein and its major metabolite hydroxytyrosol, derived from olives and virgin olive oil, have been shown to exert important anticancer activities both in vitro and in vivo due to their antioxidant properties. The present study analyzes the effects of the oral administration of oleuropein, hydroxytyrosol and the mixture of both phenolic compounds in rats with transplacental N-ethyl-N-nitrosourea (ENU)-induced brain tumors to analyze their potential effect against brain tumorigenesis through the modification of redox system components. Oxidative stress parameters, non-enzyme and enzyme antioxidant defense systems and blood chemistry were assayed in the different experimental groups. The treatment with oleuropein, hydroxytyrosol and/or the mixture of both phenolic compounds promotes a limited beneficial effect as anticancer compounds in our ENU-induced animal model of brain tumor. These effects occur via redox control mechanisms involving endogenous enzymatic and non-enzymatic antioxidant defense systems, and are highly dependent on the gender of the animals.

Sex differences exist in brain renin-angiotensin system-regulating aminopeptidase activities in transplacental ethyl-nitrosourea-induced gliomas.

INTRODUCTION: The renin angiotensin system (RAS) is emerging as an important target for the treatment of glioma. We had described that the local RAS is involved in vivo in tumor growth in the rat model of experimental C6 glioma implanted at the subcutaneous region, through the modification of several proteolytic regulatory enzymes of aminopeptidase type. METHODS: We analyze RAS-regulating aminopeptidase activities in plasma and brain tissue of control male and female rats and rats with transplacental ethylnitrosourea-induced gliomas. RESULTS: No differences were found either the mean total number of tumors per animal or the tumor volume between male and female animals. However, we have found increased levels in aspartyl aminopeptidase in both males and females and of aminopeptidase B only in males. On the contrary, decreased levels were found in aminopeptidase N and insulin-regulated aminopeptidase activities in both males and females, whereas aminopeptidase A only decreased in females. Decreased levels of aminopeptidase N, aminopeptidase B and insulin-regulated aminopeptidase were also shown in plasma of only female rats. CONCLUSIONS: Under the complexity of RAS cascade, the changes found suggest the predominant actions of angiotensin III against a decreased action of angiotensin II and angiotensin IV. We conclude that angiotensin peptides are involved in tumor growth in this rat model of glioma and that their role in tumor growth can be analyzed through their corresponding proteolytic regulatory enzymes, which make them new and attractive therapeutic targets beyond the use or angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs).

In vivo administration of doxazosin in rats highly decreases serum circulating levels of testosterone through a mechanism involving the testicular renin-angiotensin system.

Men are at greater risk of cardiovascular and renal diseases than women. Several hypertensive rat models also exhibit gender differences in blood pressure. Although the mechanisms responsible for these gender differences are not clear, androgens have been shown to promote hypertension. Testosterone is produced by Leydig cells under the regulation of catecholamines acting through both alpha- and beta-adrenoceptors. Some investigators have postulated a putative role of angiotensin II (Ang II) in modulating the action of gonadotropin in Leydig cells, inhibiting testosterone production. In the present work, we analysed the potential mechanism by which the testicular renin-angiotensin system (RAS) decreases the serum circulating levels of testosterone after the in vivo administration of the long-acting selective alpha(1)-adrenergic receptor antagonist doxazosin. RAS was analysed through assessment of the activity of its proteolytic regulatory enzymes. We can conclude that the testicular testosterone production, at least in rat, is regulated by catecholamines through a mechanism involving alpha(1)-adrenergic receptors and RAS, with a putative role for Ang III. Because doxazosin is usually used as a pharmacological therapy in the treatment of hypertension and benign prostatic hyperplasia, our results could also indicate that its benefits are due, at least in part, to decreased serum circulating levels of testosterone.

Analysis of caspase activities in rat mammary tumours induced by N-methyl-nitrosourea.

Normal breast development is controlled by a balance between cell proliferation and apoptosis. The balance between the two parameters is crucial for determining the growth or regression of breast tumours in response to therapies and treatments. Therefore, it is necessary to understand the role of apoptosis in tumour progression. Active caspases participate as essential elements in the execution of apoptotic mechanisms. In the present study, we analysed the activities of caspase-3, -8 and -9 as well as cytochrome c release in N-methyl-nitrosourea (NMU)-induced rat mammary tumours, in order to establish the apoptotic events that occur in tumour growth in this animal model. Forty female virgin Wistar rats were randomly divided into two groups. One group was injected intraperitoneally with three doses of 50 mg/kg body weight of NMU. The control group received the vehicle only. After 122 days of NMU injection, the rats were sacrificed and the tumours were excised and processed. Results showed that in mammary tumours induced by NMU, the apoptotic death receptor-mediated pathway is activated through caspase-3 and -8, but the apoptotic mitochondrial pathway is suppressed through a non-activating process of caspase-9 activity, despite the release of cytochrome c. In conclusion, these findings have demonstrated a suppression of the apoptotic mitochondrial pathway through a non-activating process of caspase-9 activity, despite the release of cytochrome c in mammary tumours induced by NMU. Although the apoptotic death receptor-mediated pathway is activated, it is not enough to maintain the balance between proliferation and apoptosis, and thus determine the overall growth of the tumour.

Chronic ethanol intake modifies renin-angiotensin system-regulating aminopeptidase activities in mouse cerebellum.

In developing cerebellum, where critical periods of vulnerability have been established for several basic substances, it has been extensively studied the wide array of abnormalities induced by exposure to ethanol (EtOH). However, little is known about the effects of EtOH consumption on cerebellar functions in adult individuals. Several studies show participation in cognitive activities to be concentrated in the lateral cerebellum (hemispheres), whereas basic motor functions such as balance and coordination are represented in the medial parts of the cerebellum (vermis and paravermis). In addition to the circulating renin angiotensin system (RAS), a local system has been postulated in brain. The effector peptides of the RAS are formed via the activity of several aminopeptidases (AP). The present work analyses the effect of chronic EtOH intake on the RAS-regulating AP activities in the soluble and membrane-bound fractions of two cerebellar locations: the hemispheres and the vermis. We hypothesize that cerebellar RAS is involved in basic motor functions rather than in cognitive activities.

Angiotensinase activity in mice fed an olive oil-supplemented diet.

We evaluated the influence of a diet supplemented with olive oil (20% by weight) (OO) on the activity of glutamyl aminopeptidase (GluAP) and aspartyl aminopeptidase (AspAP), which are involved in angiotensin metabolism. Serum concentrations of total cholesterol and fatty acids were also measured. Animals fed on the OO diet gained significantly more weight than did controls from the second week until the end of the feeding period. Serum total cholesterol concentration was significantly higher in the OO group than in control mice. Total monounsaturated fatty acids increased in OO-fed animals, but total saturated fatty acids decreased. No differences between the two groups were observed for total polyunsaturated fatty acids. Serum from animals fed on the OO diet contained significantly lower proportions of myristic, pentadecanoic, palmitic, palmitoleic, vaccenic, alpha-linolenic, gamma-linolenic, and 11,14-eicosadienoic acids than did serum from control animals. In contrast, the OO group had higher levels of oleic, stearic, and gondoic acids. GluAP activity decreased significantly in the serum of OO-fed animals. In these animals soluble AspAP activity was significantly higher in the testis, and significantly lower in the lung and adrenal, in comparison to controls. Membrane-bound AspAP activity was higher in the testis and atrium, and lower in lung, in the OO group. Soluble GluAP activity was significantly lower in the testis of OO-fed animals. Membrane-bound GluAP activity did not differ between the two groups in any of the tissues analyzed. Serum AspAP and GluAP activities correlated negatively with palmitoleic and vaccenic acid respectively in the OO group. However, no significant correlations were found in the control group. These results may reflect functional changes in the renin-angiotensin system in the serum, adrenal, testis, lung and atrium after feeding with a diet enriched in olive oil.

Pituitary aminopeptidase activities involved in blood-pressure regulation are modified by dietary cholesterol: sex differences.

Given that the existence of a local renin-angiotensin system (RAS) in the pituitary and its participation in the regulation of blood pressure and other biological functions are widely accepted, the aim of this work is to analyze the influence of dietary cholesterol on the activity of the enzymes involved in the metabolism of the effector peptides of the renin-angiotensin system (angiotensin II and III) and vasopressin, in the pituitary of male and female mice fed on a cholesterol-enriched diet (1% cholesterol and 0.5% cholic acid). Soluble and membrane-bound pituitary aminopeptidase A (aspartyl- and glutamyl-aminopeptidase), aminopeptidase M (alanyl-aminopeptidase), aminopeptidase B (arginyl-aminopeptidase) and cystinyl-aminopeptidase activities were fluorimetrically measured. In female mice, cholesterol-enriched diet produced a significant increase in soluble aspartyl- and membrane-bound aspartyl- and glutamyl-aminopeptidase activities, and a significant decrease in membrane-bound alanyl-, arginyl- and cystinyl-aminopeptidase activities. In male mice, after feeding the diet, a significant increase in soluble glutamyl- and membrane-bound arginyl-aminopeptidase activities was observed. Our results indicate differential effects of dietary cholesterol on the metabolism of angiotensin II and III and vasopressin in the pituitary of male and female mice.

Calcium-dependent modulation by ethanol of mouse synaptosomal pyroglutamyl aminopeptidase activity under basal and K(+)-stimulated conditions.

We studied the in vitro effects of ethanol (25, 50 and 100 mM) on pyroglutamyl aminopeptidase activity (pGluAP), which has been reported as thyrotrophin-releasing-hormone-degrading activity. pGluAP was measured in presence or absence of calcium, under basal and K(+)-stimulated conditions, in synaptosomes and their incubation supernatant, using pyroglutamyl-beta-naphthylamide as substrate. In basal conditions, in synaptosomes, pGluAP was inhibited by ethanol in a calcium-independent way. In the supernatant, the response differed depending on the concentration of ethanol. Depolarization with K(+) modified pGluAP in synaptosomes and supernatant depending on the presence or not of calcium. In synaptosomes, in absence of calcium, the activity was inhibited at the highest concentrations of ethanol. In contrast, in the supernatant, under depolarizing conditions, ethanol increases pGluAP in absence of calcium. These changes may be in part responsible of the behavioural changes associated to alcohol intake.

Acetylcholinesterase inhibitor SDZ ENA 713 (Rivastigmine) increases brain pyrrolidone carboxyl peptidase activity.

Pyroglutamyl-ended forms of amyloid-beta-peptide are present in senile plaques in some individuals with Alzheimer type dementia. Single oral administration of the acetylcholinesterase inhibitor SDZ ENA 713 (rivastigmine (+)-(S)-N-ethyl-3-[(1-dimethylamino)ethyl]-N-methylphenylcarbamate hydrogen tartrate) increases basal and K(+)-stimulated pyrrolidone carboxyl peptidase (Pcp) activity in mice frontal cortex synaptosomes in a dose-dependent manner. These results suggest that this drug may ameliorate ATD cognitive deficits acting not only facilitating cholinergic transmission but also avoiding the formation of pyroglutamyl-ended amyloid-beta-peptides (A beta pE) deposition through the activation of Pcp.

Serum oxytocinase activity is related to tumor growth parameters in N-methyl nitrosourea induced rat breast cancer.

Oxytocinase has been reported to hydrolyse the peptide hormone oxytocin (OT). We have previously described changes in oxytocinase activity in human breast cancer, where a highly significant increase occurred in tumoral tissue. In the present work, we analysed oxytocinase activity in serum of rats with breast cancer induced by N-methyl-nitrosourea (NMU). We also correlated these data with the number and size of tumors and the body weight of the animals to evaluate the putative value of this activity as a biological marker of the disease. Our results confirm the involvement of OT in carcinogenesis and suggest a mayor role for oxytocinase activity in the development of breast cancer.

[Structure and functions of the macroglia in the central nervous system. Response to degenerative disorders]. / Estructura y funciones de la macroglía en el sistema nervioso central. Respuesta a procesos degenerativos.

INTRODUCTION: Glial cells have been known for a long time. For many years they have been considered to be merely a support for the structure of nervous tissue. Our limited knowledge of these cells has been mainly due to different methodological problems which made it impossible to discover more about their origin and physiology. Now, however, thanks to the development of immunocytochemical techniques, it has been possible to determine their structure, and their function have been discovered thanks to the modern molecular biology techniques. Thus the importance of the glia in the nervous system, both in normal and in pathological conditions, is now realized. In recent years increasing interest has been shown in the functional role played by macroglia (astrocytes and oligodendrocytes). DEVELOPMENT: Although astrocytes and oligodendrocytes have been classified into different types, according to their morphology, these cells are functionally very heterogeneous depending on the microenvironment in which they are found. However, this is only a measure of the number of key processes in which they participate to the correct functionality of central nervous system. CONCLUSIONS: The diversity of processes in which astrocytes and oligodendrocytes are involved shows that these cells can respond in different ways to neurodegenerative situations, both normal and pathological, in order to maintain the structural integrity of cerebral tissue. Although the role played by oligodendrocytes is less well-known than that played by astrocytes, both cell types may be perfect targets for treatment of nervous system diseases, and also of the neurodegenerative changes due to ageing.

[The molecular basis of neurodegenerative processes in the central nervous system]. / Bases moleculares de los procesos neurodegenerativos en el sistema nervioso central.

INTRODUCTION: Investigations carried out in recent years indicate that there are three main mechanisms responsible for neurodegenerative processes affecting the central nervous system, particularly in advanced age. DEVELOPMENT: Of these three mechanisms, the first is based on the existence of errors associated with the pathways responsible for cell energy metabolism. Secondly, there is the formation of free radicals for different reasons. Finally, there is the hyperexcitability of amino-acid neurotransmitters, particularly glutamate acid. However, these three mechanisms which induce degeneration and neurone death seem to share a common factor: The increase in free calcium levels in the cytosol. CONCLUSIONS: Control of the maintenance of suitable levels of free Ca2+ in the cytosol, by means of drugs, may be of great help in preventing the intellectual deterioration which occurs in persons with different neurodegenerative disorders.

[Quantitative and cytomorphometric analysis of glial population in the frontal cortex of contralaterally lesioned rats]. / Análisis cuantitativo y citomorfométrico de la población glial en la corteza frontal de ratas con lesiones contralaterales.

INTRODUCTION: In the last years, the changes in glial cells during different alterations in the Central Nervous System have been studied. It is known that astrocytes and microglial cells are the glial cells which present the major reactivity. OBJECTIVE: The aim of this work was to analyze the glial cell changes induced by a lesion. MATERIAL AND METHODS: We studied the quantitative and morphometric changes observed in glial cells in the different layers of contralateral frontal cortex using micrometric techniques and image analysis. RESULTS: In contralateral side to the lesions, we observed an increase in the total glial cells in all the cortical layers. The astrocytes only increased their number in cortical layer I, but microglia and oligodendrocytes increased in all the layers. In the cytomorphometric analysis an increase in the nucleus area of astrocytes was observed. CONCLUSION: The glial cell response to the lesions is different for astrocytes, microglia and oligodendrocytes but these changes affected to all the cortical layers.

[Neuronal changes induced by degenerative processes in the central nervous system. The influence of normal and pathological aging]. / Alteraciones neuronales inducidas por procesos degenerativos en el sistema nervioso central. Influencia del envejecimiento normal y patológico.

INTRODUCTION: In the last years, an important effort has been made to know which are the causes of the neurodegenerative processes in the Central Nervous System and the morphological changes occurred under pathological situations and/or with normal ageing. DEVELOPMENT: Usually, neurodegenerative disorders have been associated with neuronal loss and reactive gliosis. However, the quantitative studies showed different or although contradictory results. These results are variable depending on the animal model, cerebral area or the technical procedure. However, there are other neuronal changes related with neurodegeneration. One of them is the presence of dark neurons. These neurons have been characterized by their strong staining and their structural and ultrastructural changes. CONCLUSIONS: In the present work we review about these neuronal changes in the literature, and the knowledge about the quantitative changes observed in two degenerative disorders: aging and induced cerebral lesions. In this way, we study normal and pathological neurodegenerative processes.

[Influence of alcohol on brain aminopeptidases. An in vitro study]. / Influencia del alcohol sobre las aminopeptidasas cerebrales. Un estudio in vitro.

INTRODUCTION: It is well known the depressor effect of alcohol on several inhibitory nervous centres. This can be due to the inhibition that induces in the release of different type of neurotransmitters, and because alcohol can increase the membrane fluidity and changes the function of proteins inserted in the membrane. Several aminopeptidases (AP) have been described as enzymes that regulate the activity of peptide neurotransmitters. In the present work, the influence of alcohol (25, 50 and 100 mM) on several aminopeptidase activities (alanyl AP, arginyl AP, cystinyl AP, leucyl AP and tyrosyl AP) has been determined in synaptosomes obtained from the cortex of mouse, under basal and K+ stimulated conditions and their calcium dependence, in a non toxic in vitro model. MATERIAL AND METHODS: AP activities were determined using aminoacyl ? naphthylamides as substrates. Non toxic in vitro model were demonstrated analyzing free radical generation, lipid peroxidation and oxidation of synaptosomal proteins. In addition, the bioenergetic behavior of synaptosomes was determined under different experimental protocols. RESULTS: In basal conditions, alcohol produces a dose related inhibition of alanyl AP activity. The rest of activities show a biphasic behavior. In this way, depending on the concentration of alcohol used, aminopeptidases are inhibited or stimulated. Depolarization with K+ 25 mM leads to a decrease of alanyl AP and tyrosyl AP activities but does not change the rest of activities. The presence of alcohol under stimulated conditions produces the inhibition of all the enzymatic activities, specially with the highest concentrations used. CONCLUSIONS: Alcohol modifies several aminopeptidase activities from synaptosomes of the cortex of mouse, acting in different ways under basal or stimulated conditions. These effects seem not to be related with degenerative events induced by alcohol. Therefore, a specific effect of this substance on the neurotransmisory/neuromodulatory systems mediated by neuropeptides must exist, modifying the enzymes that are responsible of their degradation.

[Influence of estradiol on pyroglutamyl aminopeptidase activity in the frontal cortex of ovariectomized mice]. / Influencia del estradiol sobre la actividad piroglutamato aminopeptidasa en la corteza frontal de ratones ovaridectomizados.

INTRODUCTION: Pyroglutamyl aminopeptidase (pGluAP) is an omega peptidase widely distributed in fluid and tissues which hydrolyses biological active peptides including thyrotropin releasing hormone (TRH). OBJECTIVES. The aim of present work is to study the influence of estradiol on soluble and membrane bound pGluAP activity in the frontal cortex of female mice. MATERIAL AND METHODS: Soluble and membrane bound pGluAP activities in frontal cortex of ovariectomized mice and ovariectomized mice injected with different doses of estradiol were measured using espectrophotometric assays. RESULTS: Soluble pGluAP activity in frontal cortex did not change after ovariectomy or after the administration of the different doses of estradiol. However, membrane bound pGluAP activity showed a significant increase after ovariectomy. After the administration of the lower dose of estradiol, membrane bond pGluAP activity returned to the same levels detected before the ovariectomy. CONCLUSION: Estradiol modifies membrane bound pGluAP activity which is the principal enzyme involved in the hydrolysis of TRH. Therefore, misregulation of estradiol levels may produce modifications in the neuromodulatory functions of TRH.

[Natural neurotoxins as pharmacological tools for the study of the central nervous system]. / Las neurotoxinas naturales como herramientas farmacológicas para el estudio del sistema nervioso central.

INTRODUCTION: Natural venoms produced by different species of animals are very useful to distinguish between the different types and subtypes of ionic channels and neurotransmitters receptors involved in the information processing in the nervous system. DEVELOPMENT: Natural venoms permit distinction between the different types and subtypes of Na+, K+ and Ca2+ channels. These differences are based on their structure, physical and chemical characteristics and function with regard to ionic transport and the neurotransmitters release. CONCLUSIONS: The use of different molecular biology techniques makes it possible to develop new synthetic toxins, by means of which new perspectives appear for the study and treatment of different neurological disease.

[The influence of oleic acid on the aminopeptidase activity in astrocytes of the rat]. / Influencia del ácido oleico sobre la actividad aminopeptidasa de astrocitos de rata.

INTRODUCTION: Changes in fatty acid composition of membrane lipids induce modifications on the activity of several enzymes and membrane transporters. Glial cells possess aminopeptidases which are located in the plasma membranes. Aminopeptidases are generally zinc-metalloenzymes which hydrolyze peptide bonds near the N-terminal end of peptides and polypeptides. The importance of these enzymes is based on their major role in protein metabolism and in the regulation of circulating hormones and biologically active peptides. OBJECTIVE: We study the effects of oleic acid on several aminopeptidase activities in primary cultures of rat astroglia, using aminoacyl-beta-naphthylamides as substrates. RESULTS: Oleic acid inhibits Ala-, Cys-, Leu- and Tyr-aminopeptidase activities, but not modifies Arg- and pGlu-aminopeptidase activities. CONCLUSIONS: Oleic acid modulates aminopeptidase activities in astrocytes. This could be related with intercellular communication and molecular transport processes, in which the astrocyte function has been involved. Furthermore, oleic acid might modulate the action of opioid peptides and steroid hormones on astroglial cells.

[In vitro study of the effect of ethanol on pyroglutamyl aminopeptidase activity in mouse synaptosomes under basal and stimulated conditions]. / Estudio in vitro del efecto del etanol sobre la actividad piroglutamato aminopeptidasa en sinaptosomas de ratón en condiciones basales y despolarizantes.

INTRODUCTION AND OBJECTIVE: Pyroglutamyl aminopeptidase (pGluAP) is an omega peptidase which removes pyroglutamyl N-terminals residues from peptides and arylamidase derivatives. This activity is thought to be involved in the regulation of several physiological mechanisms on the central nervous system. pGluAP can modulate various susceptible endogenous substrates such as thyrotrophin-releasing hormone (TRH). It is well known that TRH plays an important role in the modulation of the behavioral changes induced by ethanol and others drugs. The aim of this work was to study the in vitro effects of ethanol (25, 50 and 100 mM) on the pGluAP activity and its ability for modulating the TRH. MATERIAL AND METHODS: pGluAP activity was measured in synaptosomes from cerebral cortex of mouse, using pyroglutamyl-beta-naphthylamide as substrate in basal and stimulated (K+ 25 mM) conditions, and in presence or absence of calcium on the buffer. RESULTS: In basal conditions, ethanol produced an inhibition of the pGluAP activity in presence or absence of calcium, being this inhibition non dose-related. However, the stimulation with K+ 25 mM did not produce a modification of pGluAP activity in presence of calcium, but produced a light increase in absence of it. Depolarization in presence or absence of calcium and ethanol produced an inhibition of pGluAP activity, which changed in function of the ethanol concentration used. CONCLUSIONS: Ethanol modifies pGluAP activity in basal conditions by a mechanism independent of calcium, but the changes observed after the stimulation with high K+ may be due to a calcium-dependent mechanism. These variations of pGluAP activity induced by ethanol, and their effects on their endogenous substrates, specially TRH, may be responsible for the behavioral changes associated to the alcoholism and mediated by TRH.