BACKGROUND： Nikethamide, a respiratory center stimulant, is widely used in China. However, its effects on the central nervous system and medullary respiratory center remain poorly understood. OBJECTIVE： To investiga...BACKGROUND： Nikethamide, a respiratory center stimulant, is widely used in China. However, its effects on the central nervous system and medullary respiratory center remain poorly understood. OBJECTIVE： To investigate the influence of nikethamide on inspiratory neuron discharge in the medial region of the nucleus retrofacialis in neonatal rats, based on the observations addressing rhythmic respiratory discharge generated by the basic medullary respiratory center and various respiration neuron discharges in brain slices. DESIGN, TIME AND SETTING： A controlled, observational study utilizing in vitro neuroelectrophysiology was performed at the Department of Physiology in Southern Medical University between September and December in 2007. MATERIALS： Nikethamide was purchased from Sigma, USA; BL-420E biological signal collection and manaclement system was provided by Chengdu TME Technology, China.METHODS： Isolated medulla-spinal cord preparations were collected from neonatal Sprague Dawley rats, aged 1-3 days. Tissues were divided to include the medial region of the nucleus retrofacialis, ventral respiratory, and dorsal respiratory groups. Subsequently, modified Kreb＇s solution and 5 μg/mL nikethamide-containing modified Kreb＇s solution were consecutively perfused into the medial region of the nucleus retrofacialis in neonatal rat brain slices. MAIN OUTCOME MEASURES： Hypoglossal nerve root respiratory-related rhythmic discharge activities and inspiratory neuron discharges were recorded with an adsorption electrode and microelectrode. RESULTS Nikethamide resulted in prolonged inspiratory neuron discharge time, shortened respiratory cycle and expiratory time. Nikethamide intervention resulted in enhanced integral amplitude of some inspiratory neurons with no changes in discharge frequency or increased discharge frequency in remaining inspiratory neurons with no changes in integral amplitude. CONCLUSION： Nikethamide excites inspiratory neurons in the basic rhythmic respiration and medullary respiratory center, in addition to increased inspiratory neuron and neural network excitability.展开更多
Synchronization is considered to be a crucial mechanism that maintains respiratory rhythm.For understanding the effect of electrical coupling on the transition of the firing patterns and synchronization,we coupled two...Synchronization is considered to be a crucial mechanism that maintains respiratory rhythm.For understanding the effect of electrical coupling on the transition of the firing patterns and synchronization,we coupled two inspiratory pacemaker neurons together,and studied various synchronous behaviors between them.We firstly compared the bifurcation diagrams between the coupled neurons and single neuron,and found that the coupled neurons had a more complicated bifurcation mode.By increasing the coupling strength,the regular variation of phase differences was illustrated so that asynchronous and some synchronous states could be observed.These synchronous states were also shown in detail by phase portraits and firing series.In addition,we explored the ranges of different synchronous states,which attributed to different ranges of membrane capacitance and coupling strength.展开更多
基金the National Natural Science Foundation of China,No.30570670the Natural Science Foundation of Guangdong Province,No.5004714
文摘BACKGROUND： Nikethamide, a respiratory center stimulant, is widely used in China. However, its effects on the central nervous system and medullary respiratory center remain poorly understood. OBJECTIVE： To investigate the influence of nikethamide on inspiratory neuron discharge in the medial region of the nucleus retrofacialis in neonatal rats, based on the observations addressing rhythmic respiratory discharge generated by the basic medullary respiratory center and various respiration neuron discharges in brain slices. DESIGN, TIME AND SETTING： A controlled, observational study utilizing in vitro neuroelectrophysiology was performed at the Department of Physiology in Southern Medical University between September and December in 2007. MATERIALS： Nikethamide was purchased from Sigma, USA; BL-420E biological signal collection and manaclement system was provided by Chengdu TME Technology, China.METHODS： Isolated medulla-spinal cord preparations were collected from neonatal Sprague Dawley rats, aged 1-3 days. Tissues were divided to include the medial region of the nucleus retrofacialis, ventral respiratory, and dorsal respiratory groups. Subsequently, modified Kreb＇s solution and 5 μg/mL nikethamide-containing modified Kreb＇s solution were consecutively perfused into the medial region of the nucleus retrofacialis in neonatal rat brain slices. MAIN OUTCOME MEASURES： Hypoglossal nerve root respiratory-related rhythmic discharge activities and inspiratory neuron discharges were recorded with an adsorption electrode and microelectrode. RESULTS Nikethamide resulted in prolonged inspiratory neuron discharge time, shortened respiratory cycle and expiratory time. Nikethamide intervention resulted in enhanced integral amplitude of some inspiratory neurons with no changes in discharge frequency or increased discharge frequency in remaining inspiratory neurons with no changes in integral amplitude. CONCLUSION： Nikethamide excites inspiratory neurons in the basic rhythmic respiration and medullary respiratory center, in addition to increased inspiratory neuron and neural network excitability.
基金supported by the National Natural Science Foundation of China(Grant No.11172103)
文摘Synchronization is considered to be a crucial mechanism that maintains respiratory rhythm.For understanding the effect of electrical coupling on the transition of the firing patterns and synchronization,we coupled two inspiratory pacemaker neurons together,and studied various synchronous behaviors between them.We firstly compared the bifurcation diagrams between the coupled neurons and single neuron,and found that the coupled neurons had a more complicated bifurcation mode.By increasing the coupling strength,the regular variation of phase differences was illustrated so that asynchronous and some synchronous states could be observed.These synchronous states were also shown in detail by phase portraits and firing series.In addition,we explored the ranges of different synchronous states,which attributed to different ranges of membrane capacitance and coupling strength.
