Effects of N-methyl-d-aspartate and kainic acid on prolactin secretion in prepubertal female rats

Pinilla, Leonor; Gonzalez, D; Tena‐Sempere, Manuel; Aguilar, Rafaela; Aguilar, E.

doi:10.1530/eje.0.1350464

Cited by 15 publications

(21 citation statements)

References 20 publications

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“…In adult male rats, PRL secretion seems unchanged after NMDA administration (8)(9)(10), and a significant increase in serum PRL levels has been described only after orchidectomy (9). The present results show a significant inhibitory effect of NMDA on PRL secretion in prepubertal males, which agrees with data obtained in prepubertal female rats (11). The NMDA receptor mRNA is expressed in the pituitary (22) and the NMDA receptors were localized in lactotrophs (23), which explains the NMDA inhibition of PRL secretion by dispersed pituitary cells.…”

Section: Discussionsupporting

confidence: 90%

“…In adult male rats, NMDA stimulated (7) or had no effects (8-10) on PRL secretion. The effects of NMDA on PRL secretion seem to change according to the age of the animal and the endocrine milieu, as indicated by the following findings: NMDA inhibits PRL secretion in prepubertal but not in adult females (11); the stimulatory effect of NMDA on PRL secretion is observed in adult males only after orchidectomy (9); inhibitory effects of NMDA on PRL secretion are observed in hyperprolactinaemic conditions such as lactation (4,5) or after neonatal administration of oestrogens (10). Because the effects of NMDA on PRL secretion have not been analysed in prepubertal male rats, the first aim of the present experiments was to analyse the role of NMDA receptors in the secretion of PRL by prepubertal intact, orchidectomized and testosterone-treated orchidectomized males.…”

Section: Introductionmentioning

confidence: 97%

“…NO production has been shown to increase after activation of NMDA receptors (12) and NO was an important intra-or intercellular messenger involved in the control of the hypothalamic-pituitary axis (13)(14)(15)(16) and in the actions of NMDA on luteinizing hormone (LH) release (17). Sodium nitroprusside (SNP), a donor of NO, inhibited PRL secretion in vitro (18), while administration of blockers of NO synthase (NOS) inhibited basal and ovulatory secretion of PRL (11,19). The inhibitory actions of NOS blockers seemed to be mediated by an increase in hypothalamic dopamine release (11).…”

Section: Introductionmentioning

confidence: 99%

“…Sodium nitroprusside (SNP), a donor of NO, inhibited PRL secretion in vitro (18), while administration of blockers of NO synthase (NOS) inhibited basal and ovulatory secretion of PRL (11,19). The inhibitory actions of NOS blockers seemed to be mediated by an increase in hypothalamic dopamine release (11).…”

Section: Introductionmentioning

confidence: 99%

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Interactions between N-methyl-D-aspartate, nitric oxide and serotonin in the control of prolactin secretion in prepubertal male rats

Aguilar

Tena‐Sempere²,

Aguilar³

et al. 1997

European Journal of Endocrinology

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The role of N-methyl-D-aspartate (NMDA) in the control of prolactin (PRL) secretion was analysed in prepubertal male rats. In experiment 1, males of different ages were decapitated after administration of NMDA or vehicle. In experiment 2, 30-day-old males were killed at different times after administration of vehicle, NMDA, MK-801 (a non-competitive NMDA antagonist) or NMDA plus MK-801. In experiment 3, 23-day-old males were sham-orchidectomized or orchidectomized. Orchidectomized males were or were not implanted with Silastic capsules containing different amounts of testosterone. On day 30, the animals were decapitated after administration of vehicle, NMDA or MK-801. In experiment 4, 30-day-old male rats were decapitated after being injected with vehicle, NMDA, N wnitro-L-arginine methyl ester (NAME) (an inhibitor of nitric oxide (NO) synthase), or NMDA plus NAME. Serum PRL concentrations, and dopamine pituitary and hypothalamic content were measured. In experiment 5, males pretreated with vehicle or NAME were killed after administration of the precursor of serotonin synthesis 5-hydroxytryptophan (5-HTP), the 5-HT 1 receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) or the 5-HT 2 agonist (Ϯ)2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI). Finally, the effects of NMDA, NAME and sodium nitroprusside (SNP) were tested in dispersed adenohypophyseal cells. We found that: (i) antagonism of NMDA receptors with MK-801 decreased PRL secretion in intact, orchidectomized and orchidectomized-testosterone treated male rats; (ii) NMDA inhibited PRL release in vivo through an increase in dopamine release and this effect was potentiated by NAME and prevented by testosterone; (iii) NMDA inhibited PRL secretion in vitro and this effect was observed in presence of both SNP and NAME; (iv) NAME blocked the stimulatory effects of 5-HTP and DOI on PRL secretion. We conclude that endogenous glutamate stimulates PRL release and that NO might have a pivotal role in the mechanisms involved in the control of PRL release, inhibiting the release of dopamine and modulating the effects of NMDA and 5-HT. European Journal of Endocrinology 137 99-106

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Interactions between N-methyl-D-aspartate, nitric oxide and serotonin in the control of prolactin secretion in prepubertal male rats

Aguilar

Tena‐Sempere²,

Aguilar³

et al. 1997

European Journal of Endocrinology

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“…The actions of EAAs are mediated by different post-synaptic receptors which include N-methyl -aspartate (NMDA) receptors, kainate (KA) receptors, 2-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors, and metabotropic receptors (Collinbridge & Watkins 1994. Depending on the experimental paradigm, NMDA and KA either stimulated or inhibited PRL secretion (Abbud & Smith 1991, Luderer et al 1993, Carbone et al 1994, Pinilla et al 1996. It has been proposed that the effects of glutamate agonists on PRL secretion depend on the previous circulating concentrations of the hormone, with a conversion of the PRL response from stimulation when basal secretion is low to an inhibitory effect in hyperprolactinaemic situations (Abbud & Smith 1991).…”

Section: Introductionmentioning

confidence: 99%

Regulation of prolactin secretion by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors in male rats

Gonzalez

Pinilla²,

Tena‐Sempere

et al. 2000

Journal of Endocrinology

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The secretion of PRL is controlled by different hypothalamic signals. Depending on the experimental model, PRL secretion increases or decreases after activation of N-methyl--aspartic acid and kainate receptors. Recently we have described that activation of -amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors inhibits PRL secretion in prepubertal male rats. The aim of present study was to examine (1) the physiological relevance of this finding, (2) the possible age-related changes observed after activation or blockade of AMPA receptors, (3) the specificity of the AMPA effect, (4) the hypothalamic and/or pituitary localization of AMPA action, and (5) the mechanism(s) of action of AMPA agonists.In a first set of experiments, neonatal males (5 and 10 days old) and prepubertal (23 days old) male rats were injected with AMPA (1, 2·5 or 5 mg/kg) or the antagonist of AMPA receptors 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo (f) quinoxaline-7-sulfonamide (NBQX; 0·25 or 0·50 mg/kg). Serum PRL concentrations decreased significantly 15 and 30 min after i.p. administration of AMPA in prepubertal male rats, while the inhibitory effect of AMPA was not observed in 5-and 10-day-old males. The effect of AMPA was abolished by NBQX but not by MK-801 (a selective antagonist of NMDA receptors). NBQX alone (0·25 or 0·50 mg/kg) had no effect on PRL release. In vitro, AMPA slightly stimulated PRL secretion by hemipituitaries from prepubertal males, suggesting that the hypothalamus is likely the site of action for the reported inhibitory action of AMPA on PRL release. In this sense, the blockade of AMPA effects in animals pretreated with domperidone (a dopaminergic antagonist) or -methyl-p-tyrosine (an inhibitor of dopamine synthesis) suggests that an increase in the release of hypothalamic dopamine is probably the mechanism involved in the effect of AMPA. In a second set of experiments, the effects of AMPA (2·5 mg/kg i.p.) and NBQX (0·5 mg/kg i.p. and 20 or 40 nmol i.c.v.) were tested in freely moving adult male rats sampled during periods of 2, 3 or 6 h. In contrast with data obtained in prepubertal rats, neither AMPA nor NBQX affected PRL secretion.In conclusion, these data indicate that activation of AMPA receptors inhibits PRL secretion in prepubertal male rats. This effect probably involves the release of dopamine from the hypothalamus and disappears in adulthood.

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Interactions between serotoninergic and aminoacidergic pathways in the control of PRL secretion in prepubertal male rats

Pinilla

González

Tena‐Sempere

et al. 2001

J. Physiol. Biochem.

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Prolactin secretion is controlled by the hypothalamus through different neurotransmitters which interact with multiple receptor subtypes. The discovery of different families of receptors for serotonin (5-HT1-5-HT7) and excitatory aminoacids (NMDA, KA, AMPA and metabotropic receptors) ilustrates the complexity of this regulation. Moreover, in the rat the role of different neurotransmitters changes during pubertal development. Present experiments were carried out to analyse the interactions between AMPA and serotoninergic receptors in the control of prolactin secretion in prepubertal male rats. For this purpose, 16 and 23-day old male rats were treated with 5-hydroxytryptophan (5-HTP, precursor of serotonin synthesis) plus fluoxetine (blocker of serotonin reuptake), 8-OH-DPAT (agonist of 5-HT1A receptors), DOI and alpha-Me-5-HT (agonists of 5-HT2 receptors), 1-phenylbiguanide (agonist of 5-HT3 receptors) alone or in combination with AMPA (agonist of AMPA receptors). The results obtained indicate that: (a) activation of 5-HT1A receptors stimulated PRL secretion on day 16 and inhibited it on day 23; activation of 5-HT2 receptors stimulated PRL secretion on days 16 and 23, whereas activation of 5-HT3 receptors inhibited PRL release only on day 23; (b) activation of AMPA receptors inhibited PRL secretion on day 23, but not on day 16 and (c) a cross-talk is apparent between 5-HT2 and AMPA receptors in the regulation of PRL secretion, the stimulatory effect of DOI being blocked by AMPA.

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Effects of N-methyl-d-aspartate and kainic acid on prolactin secretion in prepubertal female rats

Cited by 15 publications

References 20 publications

Interactions between N-methyl-D-aspartate, nitric oxide and serotonin in the control of prolactin secretion in prepubertal male rats

Interactions between N-methyl-D-aspartate, nitric oxide and serotonin in the control of prolactin secretion in prepubertal male rats

Regulation of prolactin secretion by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors in male rats

Interactions between serotoninergic and aminoacidergic pathways in the control of PRL secretion in prepubertal male rats

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