Luteinizing hormone releasing action ofN-methyl aspartate is blocked by GABA or taurine but not by dopamine antagonists

Price, Madelon T.; Olney, John W.; Mitchell, ML; Fuller, Terry A.; Cicero, Theodore J.

doi:10.1016/0006-8993(78)90690-x

Cited by 44 publications

(21 citation statements)

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“…According to the experiments reported here, EP also induced an NMDA release response of Tau which is a putative inhibitory amino acid neurotransmitter that ap pears to be involved in the gonadotropin control [14][15][16], It is interesting to note that EP induced Tau release by NMDA indicating a regulatory effect of ovarian hor mones on the release of this amino acid. Nevertheless, more experimental evidence is needed before a conclu sion can be reached on these results, especially taking into account that the effect of Tau on gonadotropin has not yet been fully clarified.…”

Section: Discussionsupporting

confidence: 56%

“…It is difficult to explain the details of the mechanism by which EP changes its effect on hypothalamic EAA re lease during sexual maturation, but we have previously described qualitative changes in the effect of several neurotransmitters on GnRH secretion during this period of development and have proposed that these modifica tions are related to hypothalamic maturational mecha nisms which induce the onset of puberty and sexual cycles in the female rat [20][21][22], EP decreases Tau release in prepubertal rats and increases its release in peripubertal animals. Taking into account that Tau appears to inhibit gonadotropin secre tion [14][15][16], it is difficult to reconcile this finding with the negative (prepubertal) and positive (peripubertal) feedback effects of ovarian steroids on gonadotropin secretion. It is clear that more experimental evidence is needed to clarify the neuroendocrine significance of this observation.…”

Section: Discussionmentioning

confidence: 99%

“…This paper describes experiments in which we determined in prepubertal (16 days) and peripubertal (30 days) control and EP-pretreated female rats the in vitro release by the anterior preoptic and medial basal hypotha lamic areas (APOA-MBH) of aspartate (Asp), glutamate (Glu) and glycine (Gly) which are EAAs involved in NMDA neurotransmission, and taurine (Tau), a putative inhibitory amino acid neurotransmitter of GnRH-LH secretion [14][15][16]. Given that stimulation of NMDA receptors induces modifications in the hypothalamic con tent of EAAs [17], which appears to indicate the existence of a feedback mechanism of control between stimulation of NMDA receptors and EAAs release we also determined the in vitro effect of NMDA on the hypothalamic release of Asp, Glu, Gly and Tau release as well as the influence of ovarian hormones on this effect.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Ovarian Hormones on the Hypothalamic Excitatory Amino Acids System during Sexual Maturation in Female Rats

Carbone¹,

Szwarcfarb²,

Me³

et al. 1995

Neuroendocrinology

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The present experiments were designed to study in female rats during sexual maturation: (1) the hypothalamic release of aspartate (Asp), glutamate (Glu) and glycine (Gly) which are the excitatory amino acids (EAAs) involved in NMDA neurotransmission and of taurine (Tau), a putative inhibitory amino acid of GnRH secretion; (2) the relationships between the effect of estrogen-progesterone (EP) on the release of these EAAs and the secretion of gonado-tropins, and (3) the effect of hypothalamic NMDA receptor stimulation on EAAs release by the hypothalamus as well as the effect of EP on this release. The release of EAAs by the anterior preoptic and medial-basal hypothalamic areas (APOA-MBH) is significantly higher in peripubertal than in prepubertal rats (p < 0.01). EP treatment in prepubertal rats (16 days of age) decreased LH and FSH plasmatic levels and also the in vitro release of Asp, Glu, Gly and Tau. Contrary to the observations in prepubertal rats, in 30-day-old peripubertal rats the ovarian hormones significantly (p < 0.01) increased the levels of LH and FSH as well as the release to the medium of these amino acids. In prepubertal rats, the addition of NMDA to the incubation media significantly increased the release of Asp and of Glu. The NMDA receptor agonist did not modify the hypothalamic release of Gly and Tau to the incubation media. On the other hand, pretreatment with EP did not modify either the Asp and Glu release response to NMDA or the lack of response on Gly and Tau. In peripubertal rats NMDA also significantly increased the in vitro release of Asp and Glu, but at this age pretreatment with EP significantly potentiated the release of these amino acids induced by NMDA. On the other hand, the ovarian hormones induced Gly and Tau release by NMDA, this not being observed in control rats. In conclusion, the present results indicate that during sexual maturation the in vitro release of Asp, Glu and Gly by APOA-MBH increases and Tau release decreases. EP pretreatment of prepubertal rats decreases the hypothalamic release of EAAs as well as the serum LH and FSH levels but increases both EAAs release and plasmatic gonadotropin in peripubertal rats. On the basis of these results it is proposed that the increase in EAAs release by the hypothalamus is directly connected with the onset of puberty and that the maturation of the positive feedback effect of ovarian hormones on gonadotropin secretion is related to the maturation of the capacity of EP to increase hypothalamic EAAs. Before this maturational event EP inhibits EAAs release as well as gonadotropin release (prepubertal rats). NMDA receptor stimulation leads to a positive mechanism which increases the release of Asp and Glu from APOA-MBH both in prepubertal and peripubertal rats, but EP potentiates this mechanism only in peripubertal rats. This could be an additional neuroendocrine mechanism involved in the increase of gonadotropin during sexual maturation which induces the onset of puberty and the preovulatory discharge of these pituitary hormones.

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Section: Discussionsupporting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Ovarian Hormones on the Hypothalamic Excitatory Amino Acids System during Sexual Maturation in Female Rats

Carbone¹,

Szwarcfarb²,

Me³

et al. 1995

Neuroendocrinology

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“…Moreover, hyperprolactinemia modifies TAU content in the hypophysiotropic area of the hypothalamus [21]. All these data confirm the existence of interactions between TAU and prolactin [14,15,18] that may be involved in the modulation not only of hypothalamic pituitary axis activity but also in other physiological functions, like the immune response [22]. Analysis of the effects of superior cervical ganglionectomy on hypothalamic and median eminence TAU content, together with the associated changes in prolactin, GH and ACTH plasma levels will enable a better understanding of the neurochemical changes that occur after acute or chronic superior cervical ganglionectomy in the areas mentioned before.…”

Section: Introductionsupporting

confidence: 61%

“…There is also increasing evidence showing that TAU affects the hypothalamic pituitary activity through modifications in somatostatin [14], LH-stimulated or LHRH release [15,16]. TAU also has a stimulatory effect on prolactin secretion [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Superior Cervical Ganglionectomy Effects on Median Eminence and Anterior and Mediobasal Hypothalamic Taurine Content in Male Rats: Effects of Hyperprolactinemia

Esquifino

Álvarez²,

Pérez-Ferro³

et al. 2003

Neurosignals

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The neuroendocrine sequelae of acute or chronic superior cervical ganglionectomy in control or pituitary-grafted rats were studied by analyzing both plasma prolactin, growth hormone (GH) and ACTH levels, and taurine (TAU) content in the hypophysiotropic area of the hypothalamus or the median eminence. As expected, after either acute or chronic ganglionectomy, norepinephrine (NE) content decreased in the brain areas studied, although the values remained higher in hyperprolactinemic rats. TAU content was differentially modified by acute vs. chronic surgeries, thus indicating the possible existence of hypothalamic interactions between TAU and NE to regulate pituitary hormone secretion. Indeed, associated differential changes in plasma prolactin, GH and ACTH levels may be due to the observed TAU changes. As expected, pituitary grafting increased plasma prolactin, GH and ACTH levels, so that the presence of a pituitary graft differentially interferes with the effects of either surgery not only on TAU content but also on the plasma levels of the hormone studied. Globally, ongoing studies confirm the differential effects of acute and chronic superior cervical ganglionectomy on plasma prolactin, GH and ACTH levels, and provide new evidence about its effects on TAU content in the hypophysiotropic area of the hypothalamus and the median eminence that may partially explain the changes observed in the pituitary hormones studied.

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Effects Of Neurotoxic Excitatory Amino Acids On Neuroendocrine Regulation

Nemeroff¹

1983

Excitotoxins

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Luteinizing hormone releasing action ofN-methyl aspartate is blocked by GABA or taurine but not by dopamine antagonists

Cited by 44 publications

References 5 publications

Effect of Ovarian Hormones on the Hypothalamic Excitatory Amino Acids System during Sexual Maturation in Female Rats

Effect of Ovarian Hormones on the Hypothalamic Excitatory Amino Acids System during Sexual Maturation in Female Rats

Superior Cervical Ganglionectomy Effects on Median Eminence and Anterior and Mediobasal Hypothalamic Taurine Content in Male Rats: Effects of Hyperprolactinemia

Effects Of Neurotoxic Excitatory Amino Acids On Neuroendocrine Regulation

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