Dopamine–melatonin neurons in the avian hypothalamus and their role as photoperiodic clocks

Halawani, Mohamed E. El; Kang, Seong Wook; Leclerc, B.; Kosonsiriluk, Sunantha; Chaiseha, Yupaporn

doi:10.1016/j.ygcen.2008.11.030

Cited by 43 publications

(28 citation statements)

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“…colder temperatures and a scarcity of suitable habitat and food, and subsequent relocation for migratory species. While considerable attention has been focused on defining the photoperiod-induced initiation of avian reproduction, the mechanisms underlying the onset of photorefractoriness remain hidden [5,6,19,20,21,22,23,24]. Considering the ability of the PMM to receive and interpret the light stimulus [10], we speculate that the failure of the photoperiodic entrainment in this nucleus may lead to the onset of photorefractoriness.…”

Section: Introductionmentioning

confidence: 99%

GABAergic Neurotransmission in the Premammillary Nucleus of the Turkey Hypothalamus Regulates Reproductive Seasonality and the Onset of Photorefractoriness

et al. 2015

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Background/Aims: Photoperiod is a major environmental cue in temperate-zone birds which synchronizes breeding with the time of year that offers the optimal environment for offspring survival. Despite continued long photoperiods, these birds eventually become refractory to the stimulating photoperiod and their reproductive systems regress. In this study, we characterized the role of γ-aminobutyric acid (GABA)ergic neurotransmission in modulating the response of the premammillary nucleus (PMM) to a gonad stimulatory photoperiod and the onset of photorefractoriness. Methods and Results: Bilateral ablation of the PMM blocked the light-induced neuroendocrine response from occurring in photosensitive turkeys. Microarray analyses revealed an increase in GABAergic activity in the PMM of photorefractory birds as opposed to photosensitive ones, and this enhanced GABAergic activity appeared to inhibit the photoperiodic signal. Additionally, GABA_A and GABA_B receptors were expressed by dopamine-melatonin neurons in the PMM, and the administration of the GABA receptor agonist baclofen blocked the photoperiodic reproductive neuroendocrine responses. Conclusions: Consistent with the present findings, we propose that the long-sought-after mechanism underlying photorefractoriness is linked to the inhibitory actions of GABA. We suggest that (1) GABAergic interference with photoperiodic entrainment in the PMM initiates the photorefractory state and terminates the annual breeding season in temperate-zone birds, and (2) the PMM is a site of photoreception and photorefractoriness that controls the initiation and termination of avian reproductive seasonality.

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Section: Introductionmentioning

confidence: 99%

GABAergic Neurotransmission in the Premammillary Nucleus of the Turkey Hypothalamus Regulates Reproductive Seasonality and the Onset of Photorefractoriness

et al. 2015

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“…Based on the findings espoused in this hypothesis, the newer concepts of the role of both dopamine adducts (Hamilton, Blum, & Hirst, 1980; Sallstrom Baum, Hill, Kiianmaa, & Rommelspacher, 1999) and darkness-induced dopamine switching provides a fruitful avenue of investigation (El Halawani, Kang, Leclerc, Kosonsiriluk, & Chaiseha, 2009). While many future studies certainly will clarify the role of gene polymorphisms (Blum, et al, 1990; Wang, Simen, Arias, Lu, & Zhang, 2013) and related behavioral endophenotypes, the concept that all roads lead to dopamine certainly continues to be an important therapeutic target ultimately leading to prevention of relapse and potential abolition of alcoholism (Balldin, Berggren, Berglund, & Fahlke, 2013; Blum, Futterman, & Pascarosa, 1977; Dahlgren et al, 2011; Self & Nestler, 1998).…”

Section: Discussionmentioning

confidence: 99%

Hypothesizing Darkness Induced Alcohol Intake Linked to Dopaminergic Regulation of Brain Function

Blum¹,

Oscar‐Berman²,

Badgaiyan³

et al. 2014

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Understanding the role of neurotransmission in the prefrontal cortex and mesolimbic brain regions has become the subject of intensive neuroscience research worldwide. In the 1970s, our group provided evidence that rats exposed to darkness significantly augmented their alcohol intake. At that time, we proposed that melatonin was the culprit. At around the same time, our laboratory, amongst a few others, proposed that dopamine-adducts with acetaldehyde to induce alcohol intake both in rodents and in humans. While the work in these areas has declined considerably over the years, more recent scientifically sound studies continue to show the importance of these earlier controversial ideas involving alcohol abuse and alcoholism. A review of the literature has provided impetus to systematically access the newer genetic and molecular neurobiological findings relevant to the physiological and psychological motives for high alcohol consumption in animals and humans alike. Thus, we hypothesize that darkness-induced alcohol intake is linked not only to serotonergic-melatonin mechanisms, but also to dopaminergic regulation of brain mesolimbic pathways involving neuronal expression switching in response to long photoperiods affecting gene expression.

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“…Currently 4 sites in the avian brain have been proposed to house DBP ( Figure 2B): 1) the lateral septal region including the lateral septal organ (LSO; Silver et al, 1988;Kuenzel, 1993;Kuenzel and Blähser, 1994;Saldanha et al, 1994;Kuenzel et al, 1997;Wada et al, 2000;Saldanha et al, 2001;Li et al, 2004;Chaurasia et al, 2005;Rathinam and Kuenzel, 2005;Li and Kuenzel, 2008), 2) the PVN (Soni and Foster, 1997;Tomonari et al, 2007;Halford et al, 2009;Davies et al, 2012), 3) premammillary nucleus (PMM; Kang et al, , 2010Thayananuphat et al, 2007;El Halawani et al, 2009;Kosonsiriluk et al, 2013), and 4) the paraventricular organ (PVO; Vigh-Teichmann et al, 1980;Vigh and Vigh-Teichmann, 1998;. It could be that all 4 brain areas contain DBP and are functionally coordinated to ensure continual function of the essential detection of photoperiodic information.…”

Section: (1) Sensory Photopigment System Involves Deep-brain Photorecmentioning

confidence: 99%

Exploring avian deep-brain photoreceptors and their role in activating the neuroendocrine regulation of gonadal development

2015

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In the eyes of mammals, specialized photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGC) have been identified that sense photoperiodic or daylight exposure, providing them over time with seasonal information. Detectors of photoperiods are critical in vertebrates, particularly for timing the onset of reproduction each year. In birds, the eyes do not appear to monitor photoperiodic information; rather, neurons within at least 4 different brain structures have been proposed to function in this capacity. Specialized neurons, called deep brain photoreceptors (DBP), have been found in the septum and 3 hypothalamic areas. Within each of the 4 brain loci, one or more of 3 unique photopigments, including melanopsin, neuropsin, and vertebrate ancient opsin, have been identified. An experiment was designed to characterize electrophysiological responses of neurons proposed to be avian DBP following light stimulation. A second study used immature chicks raised under short-day photoperiods and transferred to long day lengths. Gene expression of photopigments was then determined in 3 septal-hypothalamic regions. Preliminary electrophysiological data obtained from patch-clamping neurons in brain slices have shown that bipolar neurons in the lateral septal organ responded to photostimulation comparable with mammalian ipRGC, particularly by showing depolarization and a delayed, slow response to directed light stimulation. Utilizing real-time reverse-transcription PCR, it was found that all 3 photopigments showed significantly increased gene expression in the septal-hypothalamic regions in chicks on the third day after being transferred to long-day photoperiods. Each dissected region contained structures previously proposed to have DBP. The highly significant increased gene expression for all 3 photopigments on the third, long-day photoperiod in brain regions proposed to contain 4 structures with DBP suggests that all 3 types of DBP (melanopsin, neuropsin, and vertebrate ancient opsin) in more than one neural site in the septal-hypothalamic area are involved in reproductive function. The neural response to light of at least 2 of the proposed DBP in the septal/hypothalamic region resembles the primitive, functional, sensory ipRGC well characterized in mammals.

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Dopamine–melatonin neurons in the avian hypothalamus and their role as photoperiodic clocks

Cited by 43 publications

References 42 publications

GABAergic Neurotransmission in the Premammillary Nucleus of the Turkey Hypothalamus Regulates Reproductive Seasonality and the Onset of Photorefractoriness

GABAergic Neurotransmission in the Premammillary Nucleus of the Turkey Hypothalamus Regulates Reproductive Seasonality and the Onset of Photorefractoriness

Hypothesizing Darkness Induced Alcohol Intake Linked to Dopaminergic Regulation of Brain Function

Exploring avian deep-brain photoreceptors and their role in activating the neuroendocrine regulation of gonadal development

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