GABA release in the medial preoptic area of cyclic female rats

Mitsushima, Dai; Shwe, Tin Tin Win; Funabashi, Toshiya; Shinohara, Kazuyuki; Kimura, Fukuko

doi:10.1016/s0306-4522(02)00160-4

Cited by 56 publications

(48 citation statements)

References 35 publications

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“…In contrast, activation of glutamate receptors consistently stimulates GnRH neurons and LH surge release (Brann and Mahesh, 1995;Gore, 2001;Kuehl-Kovarik et al, 2002). Consistent with these findings, induction of LH surge release requires suppression of GABA and stimulation of glutamate release into the POA (Petersen et al, 2003), changes that occur at the onset of the afternoon surge (Jarry et al, 1995;Mitsushima et al, 2002). These changes are triggered, at least in part, by neurons of the suprachiasmatic nucleus (SCN) that communicate photoperiodic signals to ER-containing cells in the AVPV (de la Iglesia et al, 1995;Watson et al, 1995).…”

Section: Introductionmentioning

confidence: 64%

Dual-Phenotype GABA/Glutamate Neurons in Adult Preoptic Area: Sexual Dimorphism and Function

Ottem¹,

Godwin²,

Krishnan³

et al. 2004

J. Neurosci.

188

168

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It is generally assumed that the inhibitory neurotransmitter GABA and the stimulatory neurotransmitter glutamate are released from different neurons in adults. However, this tenet has made it difficult to explain how the same afferent signals can cause opposite changes in GABA and glutamate release. Such reciprocal release is a central mechanism in the neural control of many physiological processes including activation of gonadotropin-releasing hormone (GnRH) neurons, the neural signal for ovulation. Activation of GnRH neurons requires simultaneous suppression of GABA and stimulation of glutamate release, each of which occurs in response to a daily photoperiodic signal, but only in the presence of estradiol (E 2 ). In rodents, E 2 and photoperiodic signals converge in the anteroventral periventricular nucleus (AVPV), but it is unclear how these signals differentially regulate GABA and glutamate secretion. We now report that nearly all neurons in the AVPV of female rats express both vesicular glutamate transporter 2 (VGLUT2), a marker of hypothalamic glutamatergic neurons, as well as glutamic acid decarboxylase and vesicular GABA transporter (VGAT), markers of GABAergic neurons. These dual-phenotype neurons are the main targets of E 2 in the region and are more than twice as numerous in females as in males. Moreover, dual-phenotype synaptic terminals contact GnRH neurons, and at the time of the surge, VGAT-containing vesicles decrease and VGLUT2-containing vesicles increase in these terminals. Thus, we propose a new model for ovulation that includes dual-phenotype GABA/glutamate neurons as central transducers of hormonal and neural signals to GnRH neurons.

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Section: Introductionmentioning

confidence: 64%

Dual-Phenotype GABA/Glutamate Neurons in Adult Preoptic Area: Sexual Dimorphism and Function

Ottem¹,

Godwin²,

Krishnan³

et al. 2004

J. Neurosci.

188

168

View full text Add to dashboard Cite

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“…Recently, GABA has been attracting attention as a food with functions such as improvement in memory and study, and relaxation (17,18). The ingestion of GABA resulted in higher rates of brain protein synthesis in sham-operated control rats, suggesting that brain function is affected.…”

Section: Discussionmentioning

confidence: 99%

Effect of Dietary γ-Aminobutyric Acid on the Brain Protein Synthesis Rate in Hypophysectomized Aged Rats

Tujioka

Ohsumi

Sakamoto

et al. 2011

J Nutr Sci Vitaminol

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SummaryThe purpose of this study was to determine whether the regulation of brain protein synthesis was mediated through changes in the plasma concentration of growth hormone (GH) when dietary ␥ -aminobutyric acid (GABA) treatment was manipulated in hypophysectomized or sham-operated aged rats. Experiments were done on four groups of hypophysectomized and sham-operated (24-wk-old) male rats given 0% or 0.5% GABA added to a 20% casein diet. The concentrations of plasma GH and fractional rates of protein synthesis in the brains increased significantly with the 20% casein ϩ 0.5% GABA compared with the 20% casein diet alone in the sham-operated rats. However GABA treatment to the basal diet did not affect the rates of protein synthesis in the hypophysectomized rats. In the cerebral cortex and cerebellum, the RNA activity [g protein synthesized/(g RNA·d)] significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was also related to the fractional rate of protein synthesis in these organs. The results suggest that treatment with GABA is likely to increase the concentrations of GH and the rate of brain protein synthesis in sham-operated rats only, not in hypophysectomized rats, and that the GABA-induced increase in the concentration of GH may be primarily responsible for changes in the brain protein synthesis. The RNA activity is at least partly related to the fractional rate of brain protein synthesis. Key Words ␥ -aminobutyric acid, growth hormone, protein synthesis, brain, ratsThe metabolic response to dietary proteins, age and hormonal factors includes marked changes in protein synthesis, especially in the liver, muscles and intestines ( 1-5 ). Protein synthesis in the brain is also sensitive to the alteration of dietary amino acid composition in young rats ( 6 , 7 ).Many investigators have reported that protein synthesis declines in specific tissues (e.g., liver or muscle) and in the whole body throughout development in mammals after weaning ( 8-10 ). We demonstrated that the rate of protein synthesis in the brain decreases with age in rats after weaning ( 11 ). In many investigations, not only age but also growth hormone (GH) deficiency has been shown to affect many functions related to the central nervous system in mammals ( 12 ). GH is well known as the anabolic hormone in protein metabolism. Several investigators have demonstrated that the protein synthesis in visceral organs, skeletal muscle and brains was increased by GH in rats ( 13 , 14 ).␥ -Aminobutyric acid (GABA) is a kind of amino acid widely distributed over the nature, and is an inhibitory transmitter compound in vertebrates ( 15 , 16 ). Recently, GABA was attracted attention as a functional food for improvement in memory and study capability, bloodpressure reduction and relaxation inducement ( 17 , 18 ). In a previous study, we reported that administration of GABA to young and aged rats increased the concentration of plasma GH and the rate of protein synthesis in the brain, and that a positive c...

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“…Recently, GABA has been attracting attention as a food with functions such as improvement of memory and study, and relaxation (16,19). The ingestion of GABA resulted in higher rates of brain protein synthesis in ovariectomized female rats, suggesting that brain function is affected.…”

Section: Discussionmentioning

confidence: 99%

“…We also reported that estrogen increased protein synthesis in the brain of ovariectomized female rats ( 15 ). On the other hand, several investigators demonstrated that estrogen stimulated the release of ␥ -aminobutyric acid (GABA) in the brain ( 16 ). GABA is a kind of the amino acid widely distributed in nature, and is an inhibitory transmitter compound in vertebrates ( 17 , 18 ).…”

mentioning

confidence: 98%

Dietary γ-Aminobutyric Acid Affects the Brain Protein Synthesis Rate in Ovariectomized Female Rats

Tujioka

Ohsumi

Horie³

et al. 2009

J Nutr Sci Vitaminol

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SummaryThe purpose of this study was to determine whether ␥ -aminobutyric acid (GABA) affects the rate of brain protein synthesis in ovariectomized female rats. Experiments were done on two groups of 24-wk-old ovariectomized female rats given 0 or 0.5% GABA added to the 20% casein diet. The concentrations of plasma growth hormone (GH) increased significantly with the 20% casein ϩ 0.5% GABA compared with the 20% casein diet alone. In the brain regions, GABA treatment to the basal diet elevated significantly the fractional and absolute rates of protein synthesis. In brain regions, the RNA activity [g protein synthesized/(g RNA·d)] significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis. The results suggest that the administration of GABA to ovariectomized female rats is likely to increase the concentrations of plasma GH and the rate of protein synthesis in the brain, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis. Key Words ␥ -aminobutyric acid, growth hormone, protein synthesis, brain, ratsThe metabolic response to dietary proteins, age and hormonal factors includes marked changes in protein synthesis, especially in liver, muscle and intestine ( 1 -5 ). Protein synthesis in the brain is also sensitive to the alteration of dietary amino acid composition in young rats ( 6 , 7 ).Many investigators have reported that protein synthesis declined in specific tissues (e.g., liver or muscle) and in the whole body throughout development in mammals after weaning ( 8 -10 ). We demonstrated that the rate of protein synthesis in the brain decreased with age in rats after weaning ( 11 ).In many investigations, not only age but also sex hormone deficiency has been shown to affect body composition and function in postmenopausal women ( 12 ). Estrogen increases tissue protein synthesis by stimulating transcriptional activity ( 13 , 14 ). We also reported that estrogen increased protein synthesis in the brain of ovariectomized female rats ( 15 ). On the other hand, several investigators demonstrated that estrogen stimulated the release of ␥ -aminobutyric acid (GABA) in the brain ( 16 ). GABA is a kind of the amino acid widely distributed in nature, and is an inhibitory transmitter compound in vertebrates ( 17 , 18 ). Recently, GABA has been attracting attention as a food with functions such as improvement of memory and study capability, bloodpressure lowering action and relaxation ( 16 , 19 ). In a previous study, we reported that the administration of GABA to young male rats increased the concentration of plasma growth hormone (GH) and the rate of protein synthesis in the brain, and resulted in a positive correlation between the rate of protein synthesis in the brain and the plasma concentration of GH ( 20 ). GH is well known as an anabolic hormone in protein metabolism. Ohsumi et al. ( 21 ) demonstrated that hypopysectomy has been shown to decrease the rate of pr...

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GABA release in the medial preoptic area of cyclic female rats

Cited by 56 publications

References 35 publications

Dual-Phenotype GABA/Glutamate Neurons in Adult Preoptic Area: Sexual Dimorphism and Function

Dual-Phenotype GABA/Glutamate Neurons in Adult Preoptic Area: Sexual Dimorphism and Function

Effect of Dietary γ-Aminobutyric Acid on the Brain Protein Synthesis Rate in Hypophysectomized Aged Rats

Dietary γ-Aminobutyric Acid Affects the Brain Protein Synthesis Rate in Ovariectomized Female Rats

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