Pineal – Brain Relationship

Trentini, G. P.; Mess, B; Gaetani, C. F. De; Rúzsás, C

doi:10.1016/s0079-6123(08)62939-8

Cited by 30 publications

(9 citation statements)

References 137 publications

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“…Thus, the possibility exists that the hypothalamus may be the target organ for the melatonin inhibition of corticosterone secretion [4,7]. This is in line with the proposal by many that the hypothalamus is an important site of me latonin action [8,9].…”

Section: Introductionmentioning

confidence: 63%

Effects of Melatonin on Hypothalamic γ-Aminobutyric Acid, Aspartic Acid, Glutamic Acid, β-Endorphin and Serotonin Levels in Male Mice

et al. 1995

Neurosignals

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Effects of melatonin on hypothalamic neurotransmitters in male mice were studied. Exogenous melatonin administered intraperitoneally significantly increased (p < 0.05) hypothalamic concentrations of aspartic acid and γ-aminobutyric acid by over 29 and 50% respectively. Conversely, hypothalamic β-endorphin concentration was significantly decreased (p < 0.05) 30 min after melatonin administration with doses between 5- and 100 µg/kg. Similarly, melatonin, at a concentration of 100 µg/kg, decreased (p < 0.05) the serotonin level in mouse hypothalamus by 46%. Melatonin, however, did not affect the concentration of hypothalamic glutamic acid over a dose range of 0.5–300 µg melatonin/kg. Our findings suggested that actions of pineal melatonin in animals such as inhibition on serum corticosterone levels might be mediated by the potentiation of activities of hypothalamic neurons containing γ-aminobutyric acid and aspartic acid or by the inhibition of the β-endorphin and serotonin hypothalamic neurons. The neurons containing glutamic acid in the hypothalamus were, however, not influenced by melatonin. Our results are in line with the suggestion that melatonin actions on adrenal corticosterone release or other endocrine secretions may be mediated by way of its actions on hypothalamic neurotransmitter activities.

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Section: Introductionmentioning

confidence: 63%

Effects of Melatonin on Hypothalamic γ-Aminobutyric Acid, Aspartic Acid, Glutamic Acid, β-Endorphin and Serotonin Levels in Male Mice

et al. 1995

Neurosignals

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“…In birds such as the quail, it has not been demonstrated unequivo cally that the pineal regulates its reproductive system. Nonetheless, short-day treatment caused gonadal atrophy in the quail which may implicate pineal and its hormone, mela tonin, involvement in the quail seasonal re productive function [4], The brain has been considered to be a major site of melatonin action [5]. Pinealectomy changes the turnover rates of neurotrans mitters in the hypothalamus, and melatonin injection appears to have the opposite effect.…”

Section: Introductionmentioning

confidence: 99%

“…Pinealectomy changes the turnover rates of neurotrans mitters in the hypothalamus, and melatonin injection appears to have the opposite effect. Implantation of a small amount of melatonin into the hypothalamus alters pituitary hor mone contents and/or secretion [5,6], The central action of melatonin is supported in part by the demonstration of 2-[125I]iodomelatonin binding sites in the brain tissues of vertebrates [7,8] including the quail [9]. But the exact neural site(s) of melatonin action on the regulation of the reproductive system re mains unclear [7], Recently, 2-[125I]iodomelatonin binding sites were also demonstrated in the rat pitu itary [10] and bird gonads [11,12].…”

Section: Introductionmentioning

confidence: 99%

Differential Effects of Short Photoperiod on 2-[<sup>125</sup>l]lodomelatonin Binding in the Testis and Brain of Quail

et al. 1993

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The affinities and densities of 2-[^I25I]iodomelatonin binding sites in the brains and gonads of male Japanese quail following short photoperiod treatment were studied. At 6 weeks old, control quail were placed under a 14 hour light/10 hour dark photo-stimulatory cycle and experimental quail were housed under a 7 hour light/17 hour dark photo-inhibitory lighting regime. Eighteen weeks after photic manipulation, the birds were killed at mid-light. The photo-inhibited quail had very small testes. Brains and testes of control and experimental quail were collected for receptor binding studies. The maximum number of binding sites (B_max) of 2-[¹²⁵I]iodomelatonin determined by saturation studies and the number of 2-[¹²⁵I]iodomelatonin binding sites determined by a one-point binding assay in the testes of short-day quail were significantly lower (p < 0.05) than those of the testes in reproductively active birds kept under long photoperiod. There was no significant difference (p > 0.05) between the testicular K_d (equilibrium dissociation constant) values of these two groups. As for the K_d and B_max of 2-[¹²⁵I]iodomelatonin binding sites in the whole brain, there were no significant differences (p > 0.05) between the two groups. The higher level of testicular 2-[¹²⁵I]iodomelatonin binding sites in photo-stimulated birds may be related to an up-regulation of melatonin receptors by the suppressed pineal melatonin secretion under long photoperiod. The lower testicular 2-[¹²⁵I]iodomelatonin binding sites under short photoperiod may be the result of down-regulation of melatonin receptors by the stimulated melatonin pattern in the photo-inhibited birds. Conversely, similar short-day treatment was ineffective in changing the characteristics of whole brain 2-[¹²⁵I]iodomelatonin binding. Whether a specific region (or regions) of the brain may be affected by photic manipulation remains to be investigated. The presence of testicular 2-[¹²⁵I]iodomelatonin binding sites and their physiological changes under different photoperiods suggest an important direct action of pineal melatonin on testicular function in quail.

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“…The cyclic change of circulating melatonin, appar ently, functions as a daily clock and/or season al calendar in many animals [4]. A major site of the clock and calendar function of melato nin is the central nervous system [5,6]. Among the two major components of the cen tral nervous system, melatonin research has mainly focused on the brain and limited work has been done on the spinal cord [7], There is convincing evidence on the potent central me latonin effects [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…A major site of the clock and calendar function of melato nin is the central nervous system [5,6]. Among the two major components of the cen tral nervous system, melatonin research has mainly focused on the brain and limited work has been done on the spinal cord [7], There is convincing evidence on the potent central me latonin effects [5,6]. Melatonin receptors have been demonstrated in the brain using radioreceptor assays and quantitative autora diographic studies.…”

Section: Introductionmentioning

confidence: 99%

Melatonin Receptors in the Spinal Cord

1997

Neurosignals

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Pineal – Brain Relationship

Cited by 30 publications

References 137 publications

Effects of Melatonin on Hypothalamic γ-Aminobutyric Acid, Aspartic Acid, Glutamic Acid, β-Endorphin and Serotonin Levels in Male Mice

Effects of Melatonin on Hypothalamic γ-Aminobutyric Acid, Aspartic Acid, Glutamic Acid, β-Endorphin and Serotonin Levels in Male Mice

Differential Effects of Short Photoperiod on 2-[<sup>125</sup>l]lodomelatonin Binding in the Testis and Brain of Quail

Melatonin Receptors in the Spinal Cord

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