Effects of fetal behavioral states on renal sympathetic nerve activity and arterial pressure of unanesthetized fetal sheep

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2003-10, Vol.285 (4), p.908-R916
• Main Authors: Lumbers, Eugenie R, Yu, Ze-Yan, Crawford, Edward N
• Format: Article
• Language: English
• Subjects: Animals; Behavior, Animal; Blood Pressure - physiology; Consciousness; Electroencephalography; Electromyography; Female; Fetus - physiology; Heart Rate - physiology; Kidney - innervation; Pregnancy; Respiratory Mechanics - physiology; Sheep; Sympathetic Nervous System - physiology
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00252.2003

Department of Physiology and Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia 2052 Submitted 8 May 2003 ; accepted in final form 20 June 2003 Fetal behavior, renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), and heart rate (HR) were studied 1-3 days after surgery in seven fetal sheep (aged 127-136 days). Five behavioral states were defined from chart recordings of electrocortical (electrocorticographic; ECoG) activity and eye, limb, and breathing movements. Most records were of high-voltage ECoG (HV) or low-voltage (LV) ECoG with breathing (LV B ); 6.7 ± 1.7% were LV ECoG with no breathing (LV 0 ). RSNA was lower in LV 0 ( P < 0.001) and greater in LV B than in HV ( P < 0.05). MAP was lower in both LV states than in HV and when the fetuses went from LV to HV ( P < 0.001 to P < 0.03). HR was highest in HV ( P < 0.001). In HV and LV B and when the fetus went from LV to HV, MAP and HR were inversely related ( P = 0.012-0.003). In LV B and from LV to HV there were direct relationships between MAP and RSNA ( P = 0.0014, P = 0.08), and when the fetus went from LV to HV there was also an inverse relationship between HR and RSNA ( P = 0.02). Thus fetal RSNA, MAP, and HR are affected by behavioral state as is fetal cardiovascular control. The increase in RSNA during fetal breathing showed that there was an altered level of fetal RSNA associated with fetal breathing activity. heart rate; behavior; electrocortical activity; fetal breathing movements Address for reprint requests and other correspondence: E. R. Lumbers, Dept. of Physiology and Pharmacology, School of Medical Sciences, Univ. of New South Wales, Sydney, Australia 2052 (E-mail: e.lumbers{at}unsw.edu.au ).