Oestrogen receptor-alpha-immunoreactive neurones project to the suprachiasmatic nucleus of the female Syrian hamster.
نویسندگان
چکیده
Ovarian steroid hormones regulate circadian period and phase, but classical receptors for these hormones are absent in the circadian pacemaker localized in the suprachiasmatic nucleus of the hypothalamus (SCN). In order to determine whether effects of oestrogen may be exerted through steroid-binding systems afferent to the SCN we have performed double label immunocytochemistry for oestrogen receptor-alpha(ER-alpha) and the retrograde tracer cholera toxin B subunit (CtB) after its application to the SCN. Most of the areas that contain ER-alpha-immunoreactive (ERalpha-ir) cells also contained cells afferent to the SCN. The percentage of neurones afferent to the SCN which show ERalpha-immunoreactivity varies between areas. As many as one-third of the neurones afferent to the SCN in some parts of the preoptic area and the corticomedial amygdala are ERalpha-ir. Very few of the afferent neurones from the septum and the central grey are ERalpha-ir, whereas an intermediate proportion of afferents from the bed nucleus of the stria terminalis and the arcuate nucleus are ERalpha-ir. Our retrograde tracing results were compared with results of anterograde tracing from some of the sites containing SCN afferents. Using a combined retrograde and anterograde tracing technique we tested the possibility that single ERalpha-ir neurones afferent to the SCN could receive reciprocal innervation by SCN efferents. Although we found SCN input to some SCN afferent neurones, we found no evidence of reciprocity between single ERalpha-ir cells and the SCN. Our results indicate the existence of oestrogen binding systems afferent to the SCN. These neuroanatomical pathways may mediate effects of gonadal steroid hormones on circadian rhythms.
منابع مشابه
The effects of continuous light exposure on Syrian hamster suprachiasmatic (SCN) neuronal discharge activity in vitro.
The circadian variation in neuronal discharge activity recorded in vitro from the Syrian hamster suprachiasmatic nucleus (SCN), identified as a circadian clock, was used as an index of SCN circadian function. SCN neurones (n = 89) following in vitro commissural section of the paired SCN showed a similar peak in spontaneous discharge activity during the projected light phase (between CT 06.00 an...
متن کاملVasopressin (V1a) receptor binding, mRNA expression and transcriptional regulation by androgen in the Syrian hamster brain.
Arginine vasopressin plays an important role in the regulation of social behaviours in rodents. In the Syrian hamster, vasopressin injected directly into the brain stimulates scent marking and aggressive behaviour in a steroid dependent manner and is therefore a useful model for investigating steroid-peptide-behaviour interactions. In this study, we used in situ hybridization and radioligand bi...
متن کاملNovel G protein-coupled oestrogen receptor GPR30 shows changes in mRNA expression in the rat brain over the oestrous cycle.
Oestrogen influences autonomic function via actions at classical nuclear oestrogen receptors α and β in the brain, and recent evidence suggests the orphan G protein-coupled receptor GPR30 may also function as a cytoplasmic oestrogen receptor. We investigated the expression of GPR30 in female rat brains throughout the oestrous cycle and after ovariectomy to determine whether GPR30 expression in ...
متن کاملNeurophysiological responses to melatonin in the SCN of short-day sensitive and refractory hamsters.
The pineal hormone melatonin plays a central role in the regulation of seasonal reproductive cycles in mammals and several studies have implicated the suprachiasmatic nucleus (SCN) as a target on which melatonin acts. The Syrian hamster is a long-day breeder which exhibits gonadal regression when housed in short (less than 12.5 h) daily photoperiods or injected daily with melatonin in long phot...
متن کاملEstrogen receptor-alpha-immunoreactive neurons in the mesencephalon, pons and medulla oblongata of the female golden hamster.
Recent studies have revealed brainstem-spinal pathways involved in the generation of receptive behavior in hamster and cat, and the enormous influence of estrogen on these pathways. The present study gives an overview of the location of estrogen receptor-alpha-immunoreactive neurons (ER-alpha-IR) in the brainstem of the female hamster. In the mesencephalon, ER-alpha-IR cells were found in the a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Journal of neuroendocrinology
دوره 11 7 شماره
صفحات -
تاریخ انتشار 1999