| The key to the upstream regulation of animal reproduction is the proper secretion of Gonadotropin releasing Hormone(GnRH).In order to maintain fertility,GnRH secretes along the pituitary portal system and binds to the GnRH receptor located in the pituitary gland and initiates a signal cascade.The reaction controls the cell viability of Gondadotropic Hormone(Gt H)and affects the synthesis and secretion of its hormone.Gt H is a hormone that plays a major role in animal reproduction.Two GTH hormones have been isolated and purified from a variety of teleost fish.GTH-I and GTH-II in fish correspond to pituitary follicles of mammalian body weight,respectively.Follicle stimulating Hormone(FSH)and luteinizing Hormone(LH).The Caudal Neurosecretory System(CNSS),a fish-specific neurosecretory system,is involved in the regulation of fish stress and osmotic pressure regulation.CNSS is located at the end of the fish spinal cord and can be divided into three major components: 1.Dahlgren cells that function as neurotransmitters and hormones in the neurosecretory system;2.nerves that extend outward on the Dahlgren cells.Axon;third,as a caudal body of the neurovascular organs that serve as a storage function.In the existing research,from the perspective of macro-histology and micro-molecular science,it is shown that the histological structure and endocrine regulation of CNSS have certain similarities with the hypothalamic-pituitary system,and the changes of GSI and UII expression in teleost fish The trend is similar,and the morphology of Dahlgren cells changes with the seasons,indicating that CNSS may also be involved in reproductive-related regulation.Studies have shown that the electrophysiological activity of Dahlgren cells in CNSS will produce different changes according to different drug stimuli,and drugs that can cause changes include neurotransmitters and hormonal drugs.At present,the neuroendocrine activities of fish reproduction are still the focus of research,and further understanding of reproductive-related regulatory mechanisms will contribute to the development of fisheries and aquaculture.This paper focuses on the regulation of hormone gonadotropin-releasing hormone and pituitary follicle-stimulating hormone in fish reproduction,and studies the effects of these two hormones on the regulation mechanism of Dahlgren cell discharge and the expression of cell neurosecretory.In this experiment,the effects of GnRH and FSH on Dahlgren cells were studied by electrophysiological techniques.The results show:1.In order to explore the regulation mechanism and physiological effects of GnRH on the electrophysiological activity of Dahlgren cells,GnRH drug perfusion experiments were performed in the posterior nerve of the brown gingiva,ie,the 6th section of the spinal cord,and the GnRH receptor specific antagonist was also used for antagonistic reaction.In the experiment,the perfusion samples were collected and their receptors and Dahlgren cell secretion gene expression were explored using fluorescence quantification technique.The results showed that GnRH was perfused at three concentrations(0.1 n M,1 n M,10 n M).As the concentration increased,the total discharge of the cells gradually increased.During the dosing period,the discharge pattern of Dahlgren cells changed into a short burst discharge,after discharge.There is a short-term activity reduction state,but it can be restored as it is eluted.The higher the drug concentration,the longer the first elution activity reduction state is maintained.When perfused at a concentration of 0.1 n M,the cell discharge increased slightly,but the difference was not significant.0.1n M and 1n M perfusion showed significant discharge attenuation at the first elution.It is speculated that GnRH drug will cause explosive discharge of cells when perfused,and the cells will enter a transient activity reduction state after explosive discharge.The second elution eased a slight increase in discharge.The amount of dosing discharge increased significantly at1 n M and 10 n M perfusion,and the maximum reached nearly 2,300.From the discharge type statistics,it can be seen that most of the Dahlgren cell discharge mode changes to Bursting when GnRH is perfused,and gradually returns to the original state after elution.The higher the concentration,the longer the recovery time is required.The perfusion receptor antagonist cetrorec can see a decrease in the frequency of cell discharge and even stop the discharge activity.The results of RT-q PCR showed that GnRH perfused had a certain effect on the gene expression of CNS in the receptor,and the expression of the receptor gradually increased with the increase of concentration.The m RNA expression level of CRH in CNSS after drug perfusion was decreased when perfusion of 1 n M and 10 n M concentration of GnRH.The expression level of UI was significantly increased under the stimulation of 0.1n M GnRH.The expression level of UII was significantly lower than that of the blank group,but there was no significant difference between them.2.In order to explore the regulation mechanism and physiological influence of FSH on the electrophysiological activity of Dahlgren cells,the FSH receptor specific antagonist was also used for the antagonistic reaction.The perfusion samples were collected and secreted by their quantitative receptors and Dahlgren cells.Gene expression is explored.The results showed that the discharge volume of Dahlgren cells increased significantly with the increase of drug concentration,and the highest discharge was nearly 15000 when perfusion of 10 IU FSH.At the time of dosing,as the concentration increases,the cell discharge mode is largely changed from the silent mode to the bursting mode,and such a change can be gradually restored as the elution time increases.The higher the perfusion drug concentration,the longer the elution time required for the cells to return to the original discharge mode.At the time of 5 IU drug perfusion,the overall discharge volume did not change significantly.It is speculated that the effect was not obvious in the in vitro perfusion experiment because the drug concentration was close to the physiological concentration.The discharge was significantly increased at 10 IU perfusion and increased significantly at 20 IU perfusion.The cell discharge pattern showed little change at low concentrations,and a small amount of phasic cells were converted to a tonic discharge mode at 10 IU perfusion and gradually recovered upon elution.At high concentrations,it changes to the bursting discharge mode.And as the elution slowly returns to its original state.FSHRI-8,a specific FSH receptor antagonist,can be seen to reduce the frequency of cell discharge,but this antagonism has some delay.RT-q PCR results showed that the expression of gene expression in CNSS was significantly affected by perfusion FSH,and the expression of receptor was significantly increased at 20 IU.Although the m RNA expression level of CRH was decreased,there was no significant change.The expression trend of UI was significantly higher under the stimulation of low-dose drugs,and the trend of gradual decrease under high-dose stimulation showed no significant difference.Similarly,under the stimulation of three different concentrations of FSH perfusion,the expression of UII was significantly lower than that of the blank group,and there was no significant difference between each concentration group. |
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