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 management 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. 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. Special Circles: Nikethamide was purchased from Sigma, USA; BL-420E biological signal collection and management 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. Dubbed, 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 c enter, in addition to increased inspiratory neuron and neural network excitability.