Melatonin rhythms in the eyes, pineal bodies, and blood of Japanese quail (Coturnix coturnix japonica)

Underwood, Herbert; Binkley, Sue; Siopes, T. D.; Mosher, Karen

doi:10.1016/0016-6480(84)90063-7

Cited by 197 publications

(69 citation statements)

References 34 publications

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“…If the retina secretes melatonin into the circulation, removal of the eyes would significantly reduce the concentration of melatonin in the blood. Reduction of serum melatonin following blinding in the quail was reported by Underwood et al [33]. However, in our laboratory, bilateral enucleation did not reduce the level of melatonin in the circulation of rats, chickens and quails [2,34], In our opinion, we used a more specific assay and our results which had been repeated a few times should be more reliable.…”

Section: Evidence For the Direct Transduction Of Light To Melatonin Smentioning

confidence: 90%

Sensory Receptors as a Special Class of Hormonal Cells

1991

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Classically, sensory receptors are specialized cells which detect specific environmental disturbances and send out neural signals for the integration, control and/or regulation of effector organs. Recently, a special class of sensory receptors called sensori-hormonal cells which employ hormones as their means of flux of biological information has been proposed. These sensori-hormonal cells are capable of detecting and transducing environmental signals directly into the secretion of hormones within the same cells. Theoretically, all sensory receptors may have examples capable of direct sensori-hormonal transduction. However, only one group of sensori-hormonal cells, the photoendocrine cells, have so far been studied. The photoendocrine cells including the photoreceptors of fish retinas and pinealocytes of bird pineals are capable of detecting light and/or darkness and transducing the electromagnetic radiation energy into a hormonal output. Generally, light suppresses and darkness stimulates the biosynthesis and secretion of melatonin by these photoendocrine cells. Contrary to many hormonal systems which employ principally the feedback mechanism for regulation, the sensori-hormonal cells are predominantly controlled by the feedforward mechanism. However, other factors may serve as additional means of regulation by influencing the system and affecting the transduction processes and/or the synthesis and secretion of the hormone. The ability of sensori-hormonal transduction is suggested to be important for the survival of the organism itself and/or its species and sensori-hormonal cells or their equivalent should appear early in the course of animal evolution. It is further suggested that the sequence of appearance of melatonin functions in the course of evolution would be: hormone – humoral factor – neuromodulator – neurotransmitter.

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Section: Evidence For the Direct Transduction Of Light To Melatonin Smentioning

confidence: 90%

Sensory Receptors as a Special Class of Hormonal Cells

1991

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“…Ubuka et al (2005) therefore hypothesized that melatonin may be involved in the induction of GnIH expression. The pineal gland and eyes are the major sources of melatonin in quail (Underwood et al, 1984). Pinealectomy (Px) combined with orbital enucleation (Ex) (Px plus Ex) decreased the expression of GnIH precursor mRNA and GnIH peptide in the hypothalamus and melatonin administration to Px plus Ex birds caused a dose-dependent increase in the expression of GnIH precursor mRNA and GnIH peptide.…”

Section: Regulation Of Seasonal Reproductionmentioning

confidence: 99%

Molecular, cellular, morphological, physiological and behavioral aspects of gonadotropin-inhibitory hormone

Ubuka

Son

Tsutsui

2016

General and Comparative Endocrinology

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“…In this experiment, we investigated the effect of melatonin on the production of 7␣-and 7␤-hydroxypregnenolone in the diencephalon of males. The pineal gland and eyes are the major sources of melatonin in the quail (Underwood et al, 1984). Pinealectomy with orbital enucleation (Px plus Ex) and sham-operation (SH) were performed under Nembutal anesthesia as described previously (Oishi and Lauber, 1974;Ubuka et al, 2005).…”

Section: Measurements Of the Production And Concentration Ofmentioning

confidence: 99%

7α-Hydroxypregnenolone Mediates Melatonin Action Underlying Diurnal Locomotor Rhythms

Tsutsui¹,

et al. 2008

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Melatonin regulates diurnal changes in locomotor activity in vertebrates, but the molecular mechanism for this neurohormonal regulation of behavior is poorly understood. Here we show that 7␣-hydroxypregnenolone, a previously undescribed avian neurosteroid, mediates melatonin action on diurnal locomotor rhythms in quail. In this study, we first identified 7␣-hydroxypregnenolone and its stereoisomer 7␤-hydroxypregnenolone in quail brain. These neurosteroids have not been described previously in avian brain. We then demonstrated that 7␣-hydroxypregnenolone acutely increased quail locomotor activity. To analyze the production of 7␣-hydroxypregnenolone, cytochrome P450 7␣ , a steroidogenic enzyme of this neurosteroid, was also identified. Subsequently, we demonstrated diurnal changes in 7␣-hydroxypregnenolone synthesis in quail. 7␣-Hydroxypregnenolone synthesis and locomotor activity in males were much higher than in females. This is the first demonstration in any vertebrate of a clear sex difference in neurosteroid synthesis. This sex difference in 7␣-hydroxypregnenolone synthesis corresponded to the sex difference in locomotion. We show that only males exhibited marked diurnal changes in 7␣-hydroxypregnenolone synthesis, and these changes occurred in parallel with changes in locomotor activity. Finally, we identified melatonin as a key component of the mechanism regulating 7␣-hydroxypregnenolone synthesis. Increased synthesis of 7␣-hydroxypregnenolone occurred in males in vivo after melatonin removal via pinealectomy and orbital enucleation (Px plus Ex). Conversely, decreased synthesis of this neurosteroid occurred after melatonin administration to Px plus Ex males. This study demonstrates that melatonin regulates synthesis of 7␣-hydroxypregnenolone, a key factor for induction of locomotor activity, thus inducing diurnal locomotor changes in male birds. This is a previously undescribed role for melatonin.

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Melatonin rhythms in the eyes, pineal bodies, and blood of Japanese quail (Coturnix coturnix japonica)

Cited by 197 publications

References 34 publications

Sensory Receptors as a Special Class of Hormonal Cells

Sensory Receptors as a Special Class of Hormonal Cells

Molecular, cellular, morphological, physiological and behavioral aspects of gonadotropin-inhibitory hormone

7α-Hydroxypregnenolone Mediates Melatonin Action Underlying Diurnal Locomotor Rhythms

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