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Acute alcohol administration induces a time dependent increase in proenkephalin gene expression in brain rats
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Acute alcohol administration induces a time dependent increase in proenkephalin gene expression in brain rats
J.M. Oliva, S. P~rez, L. Urigiien*, S. Ortiz, G. Ponce, G. Rubio, T. Palomo, J. Manzanares. Servicio de Psiquiatria and Unidad
de Investigaci6n, Hospital Universitario 12 de Octubre, Avda. Cordoba s/n, 28040, Madrid, Spain A number of studies suggests the involvement of the endogenous opioid systems as a relevant part of the neurobiological mechanisms functionally involved in alcohol reinforcement and addiction. Acute alcohol intake may affect the endogenous opioid system enhancing the sensitivity of alcohol addiction in key regions (hypothalamic and limbic structures) closely related with the regulation of addictive behavior. The purpose of this study was to examine the time course of the effects of acute alcohol administration on proenkephalin (PENK) gene expression in selected hypothalamic and limbic structures. Male Wistar rats weighing 250-275 g were administered with alcohol (3 g/kg; p.o.; 0.5, 1, 2, 4, 8 and 24 h) and at the appropriated time points animals were killed by decapitation and their brains were quickly removed and frozen over dry ice. Coronal brain 10 gm sections at the level paraventricular nucleus (PVN), Central (Ce) and medial (Me) amygdaloid nuclei and ventromedial nucleus (VMN) were mounted onto gel slides and stored at -80°C until the day of the assay. In situ hybridization histochemistry assay was carried out to measure PENK mRNA levels. The administration of acute alcohol produced a pronounced increase in PENK mRNA levels in all the brain regions examined. However, the degree of magnitude of this increase and the duration of the effect is different depending upon the brain region examined. In general, a transient decrease (20%) in PENK gene expression was found 30 min after alcohol administration, markedly increasing by 2-4 hours in the PVN (80%), Ce (45%), Me (20%) and VMN (25%). These values returned to water treated vehicle 24 hours after alcohol administration in VMN and Me, and still remained higher at this time point in the PVN (25%) and Ce (20%). The results of this study indicate that acute alcohol administration differentially upregulates PENK gene expression in hypothalamic and limbic structures. The longer action of alcohol administration on PENK mRNA levels in PVN and Ce (more than 24 hours) in comparison to Me and VMN strongly suggests an enhanced responsiveness of these brain regions to alcohol that may be functionally relevant in the mechanisms involved in alcohol drinking reinforcement. Supported by Grant from FISS (01/1438) to J. Manzanares.
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Changes in opioid gene transcripts in alcohol preferring and non-preferring male rats
S. Ortiz, J.M. Oliva, S. P6rez*, L. Urigiien, G. Ponce, M.A. Jim~nez-Arriero, T. Palomo, J. Manzanares. Servicio de
Psiquiatria and Unidad de Investigaci6n, Hospital Universitario 12 de Octubre, Avda. Cordoba s/n, 28040, Madrid, Spain Alcohol consumption produces numerous pharmacological effects through its interaction with various neurotransmitters and neuromodulators. It has been suggested that the endogenous opioid systems may play a key role in development and maintenance of alcohol addiction.
$403
The aim of this study was to evaluate the effect of chronic ethanol intake on proenkephalin (PENK), prodynorphin (PDYN) and propiomelanocortin (POMC) gene expression in several brain and pituitary (anterior lobe, AL; intermediate lobe, IL) regions of male rats. The study was designed to examine the effects of chronic alcohol consumption on opioid gene expression. Wistar Rats weighing 250~75 g were divided into 4 groups: 1) water (W), 2) forced 10% alcohol (F), 3) alcohol preferring group (medium average of 3.5 g ethanol/kg/day), using the two bottles choice paradigm and 4) alcohol non-preferring group (NP). The study consisted in two phases: 1) acquisition of alcohol intake (3 weeks) and 2) maintenance (6 weeks). At the end of this period, animals were killed by decapitation and brains were quickly removed and frozen over dry ice. Coronal brain 10 ~tm sections at the level of caudate-putamen (CPu), nucleus accumbens (core and shell, Acbc, Acbs), paraventricular nucleus (PVN), arcuate nucleus (ARC) and pituitary regions were mounted onto gel slides and stored at -80°C until the day of the assay. In situ hybridization histochemistry assay was carried out to measure PENK, PDYN and POMC mRNA levels. PENK gene expression was markedly increased in most of the forebrain regions examined: CPu of P and NP groups (30% and 40%, respectively), Acbs (40%, 60% and 80% higher than control group in F, P and NP groups, respectively), Acbe (30%, 40%, and 80% higher than control group in F, P, and NP groups) (60% higher than control group) in the olfactory tubercle only in the NP group. In contrast, PDYN mRNA levels are significantly decreased in almost all groups of rats and brain regions. In general, decreases of PDYN gene expression between 3 0 ~ 5 % were found in CPu, Acbs, Ache, PVN and SON. It is interesting to note that the most pronounced decreases in PDYN gene expression in the brain regions examined occurred in the P group. The results showed that chronic alcohol consumption increased (20%) POMC gene expression in ARC of the hypothalamus and AL of the pituitary gland, only in the NP group, whereas a decrease in POMC mRNA levels was detected in the IL of the pituitary. Taken together, these results suggest that chronic alcohol intake differentially regulate the endogenous opioid systems in brain and pituitary regions of alcohol preferring and non-preferring rats. These changes in opioid gene transcripts may be relevant to understand the behavioral neuroplasticity of alcohol addiction. Supported by Grant from FISS (01/1438) to J. Manzanares and Grant CAM (08.5/0001.1/2000) to T. Palomo.
P.6. Other topics ~
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decrease in blood tryptophan concentration produces regionally specific changes in brain serotonin synthesis in men and women: A PET study with alpha-[11C]methyI-L-tryptophan
M, Diksic 1, S. Okazawa 1 , S. Nishizawa 2, M. Leyton 1, S.N. Young 1. tMcGill Universitv, Montreal Neurologieal
Institute, Montreal, Canada, 2Fukui Medical University Fukui, Japan We recently reported evidence that acute depletion of the essential amino acid precursor of serotonin (5-HT), L-tryptophau, produces widespread decreases in brain 5-HT synthesis, as assessed by the
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Acute alcohol administration induces a time dependent increase in proenkephalin gene expression in brain rats
J.M. Oliva, S. P~rez, L. Urigiien*, S. Ortiz, G. Ponce, G. Rubio, T. Palomo, J. Manzanares. Servicio de Psiquiatria and Unidad
de Investigaci6n, Hospital Universitario 12 de Octubre, Avda. Cordoba s/n, 28040, Madrid, Spain A number of studies suggests the involvement of the endogenous opioid systems as a relevant part of the neurobiological mechanisms functionally involved in alcohol reinforcement and addiction. Acute alcohol intake may affect the endogenous opioid system enhancing the sensitivity of alcohol addiction in key regions (hypothalamic and limbic structures) closely related with the regulation of addictive behavior. The purpose of this study was to examine the time course of the effects of acute alcohol administration on proenkephalin (PENK) gene expression in selected hypothalamic and limbic structures. Male Wistar rats weighing 250-275 g were administered with alcohol (3 g/kg; p.o.; 0.5, 1, 2, 4, 8 and 24 h) and at the appropriated time points animals were killed by decapitation and their brains were quickly removed and frozen over dry ice. Coronal brain 10 gm sections at the level paraventricular nucleus (PVN), Central (Ce) and medial (Me) amygdaloid nuclei and ventromedial nucleus (VMN) were mounted onto gel slides and stored at -80°C until the day of the assay. In situ hybridization histochemistry assay was carried out to measure PENK mRNA levels. The administration of acute alcohol produced a pronounced increase in PENK mRNA levels in all the brain regions examined. However, the degree of magnitude of this increase and the duration of the effect is different depending upon the brain region examined. In general, a transient decrease (20%) in PENK gene expression was found 30 min after alcohol administration, markedly increasing by 2-4 hours in the PVN (80%), Ce (45%), Me (20%) and VMN (25%). These values returned to water treated vehicle 24 hours after alcohol administration in VMN and Me, and still remained higher at this time point in the PVN (25%) and Ce (20%). The results of this study indicate that acute alcohol administration differentially upregulates PENK gene expression in hypothalamic and limbic structures. The longer action of alcohol administration on PENK mRNA levels in PVN and Ce (more than 24 hours) in comparison to Me and VMN strongly suggests an enhanced responsiveness of these brain regions to alcohol that may be functionally relevant in the mechanisms involved in alcohol drinking reinforcement. Supported by Grant from FISS (01/1438) to J. Manzanares.
•
Changes in opioid gene transcripts in alcohol preferring and non-preferring male rats
S. Ortiz, J.M. Oliva, S. P6rez*, L. Urigiien, G. Ponce, M.A. Jim~nez-Arriero, T. Palomo, J. Manzanares. Servicio de
Psiquiatria and Unidad de Investigaci6n, Hospital Universitario 12 de Octubre, Avda. Cordoba s/n, 28040, Madrid, Spain Alcohol consumption produces numerous pharmacological effects through its interaction with various neurotransmitters and neuromodulators. It has been suggested that the endogenous opioid systems may play a key role in development and maintenance of alcohol addiction.
$403
The aim of this study was to evaluate the effect of chronic ethanol intake on proenkephalin (PENK), prodynorphin (PDYN) and propiomelanocortin (POMC) gene expression in several brain and pituitary (anterior lobe, AL; intermediate lobe, IL) regions of male rats. The study was designed to examine the effects of chronic alcohol consumption on opioid gene expression. Wistar Rats weighing 250~75 g were divided into 4 groups: 1) water (W), 2) forced 10% alcohol (F), 3) alcohol preferring group (medium average of 3.5 g ethanol/kg/day), using the two bottles choice paradigm and 4) alcohol non-preferring group (NP). The study consisted in two phases: 1) acquisition of alcohol intake (3 weeks) and 2) maintenance (6 weeks). At the end of this period, animals were killed by decapitation and brains were quickly removed and frozen over dry ice. Coronal brain 10 ~tm sections at the level of caudate-putamen (CPu), nucleus accumbens (core and shell, Acbc, Acbs), paraventricular nucleus (PVN), arcuate nucleus (ARC) and pituitary regions were mounted onto gel slides and stored at -80°C until the day of the assay. In situ hybridization histochemistry assay was carried out to measure PENK, PDYN and POMC mRNA levels. PENK gene expression was markedly increased in most of the forebrain regions examined: CPu of P and NP groups (30% and 40%, respectively), Acbs (40%, 60% and 80% higher than control group in F, P and NP groups, respectively), Acbe (30%, 40%, and 80% higher than control group in F, P, and NP groups) (60% higher than control group) in the olfactory tubercle only in the NP group. In contrast, PDYN mRNA levels are significantly decreased in almost all groups of rats and brain regions. In general, decreases of PDYN gene expression between 3 0 ~ 5 % were found in CPu, Acbs, Ache, PVN and SON. It is interesting to note that the most pronounced decreases in PDYN gene expression in the brain regions examined occurred in the P group. The results showed that chronic alcohol consumption increased (20%) POMC gene expression in ARC of the hypothalamus and AL of the pituitary gland, only in the NP group, whereas a decrease in POMC mRNA levels was detected in the IL of the pituitary. Taken together, these results suggest that chronic alcohol intake differentially regulate the endogenous opioid systems in brain and pituitary regions of alcohol preferring and non-preferring rats. These changes in opioid gene transcripts may be relevant to understand the behavioral neuroplasticity of alcohol addiction. Supported by Grant from FISS (01/1438) to J. Manzanares and Grant CAM (08.5/0001.1/2000) to T. Palomo.
P.6. Other topics ~
A
decrease in blood tryptophan concentration produces regionally specific changes in brain serotonin synthesis in men and women: A PET study with alpha-[11C]methyI-L-tryptophan
M, Diksic 1, S. Okazawa 1 , S. Nishizawa 2, M. Leyton 1, S.N. Young 1. tMcGill Universitv, Montreal Neurologieal
Institute, Montreal, Canada, 2Fukui Medical University Fukui, Japan We recently reported evidence that acute depletion of the essential amino acid precursor of serotonin (5-HT), L-tryptophau, produces widespread decreases in brain 5-HT synthesis, as assessed by the