The Effet Of Dopamine On Thermoregulation In Bufo Gargarizans

Objective: To investigate the effect of dopamine on thermoregulation in Bufo gargarizans and provide valuable data for thermoregulation in amphibian animals.Methods: HPLC was used to measure the content of dopamine in the whole brain,diencephalon,and plasma of Bufo gargarizans at different ambient temperature(5??10??15??20??25??30?).The correlation analysis was employed between ambient temperature and the hypothalamus neurons discharge frequency.Digital thermometer was used to record the temperature variations of Bufo gargarizans after intraperitoneal injection of dopamine.Microelectrode technique was used to record extracellularly spontaneous electrical activities of neurons in diencephalon of Bufo gargarizans after intraperitoneal injection of dopamine.The contents of dopamine in diencephalon,and plasma of Bufo gargarizans after intraperitoneal injection of dopamine were measured with HPLC.Finally,the correlation analysis with the temperature variations,hypothalamus neurons discharge frequency and dopamine content was explored in detail..Results: The content of dopamine in the whole brain,diencephalon,and plasma of Bufo gargarizans has increased with the rising of the ambient temperature.Exogenous dopamine makes Bufo gargarizans body temperature decreased significantly,with the maximum decrease of 0.6? at 50 minutes after injection,then the body temperature has kept stable.Exogenous dopamine can increase the Bufo gargarizans anterior hypothalamus neurons discharge frequency,and reduce the frequency of posterior preoptic neurons.The dopamine levels decreases in the diencephalon of Bufo gargarizans within 50 min and rises between 50-90 min,while the content of dopamine in plasma decreases after intraperitoneal injection,the content of dopamine in 50 min and 90 min has no difference.Conclusion:The content of dopamine in the brain and plasma of Bufo gargarizans has increased with the rising of ambient temperature.The content of diencephalon is higher than the whole brain.Exogenous dopamine makes Bufo gargarizans body temperature decreased,exogenous dopamine can increase the Bufo gargarizans anterior hypothalamus neurons discharge frequency,and reduce the frequency of posterior preoptic neurons and play roles in thermoregulation.The dopamine levels in the diencephalon of Bufo gargarizansis decreases at first and then rises,while the content of dopamine in plasma decreases after intraperitoneal injection.