The recruitment pattern of single vasoconstrictor neurons in human.
The aim of this study is to determine the recruitment pattern among individual vasoconstrictor neurons under the baroreceptor-mediated influence in man. Spikes of single vasoconstrictor units were detected from microneurograms with a template-matching method. A total of 39 single vasoconstrictor units were detected. Single vasoconstrictor units were different from each other in their susceptibility to be activated in response to changes in the R-R interval or blood pressure. The units with higher firing probability had a shorter threshold R-R interval and a higher threshold diastolic blood pressure than units with lower firing probability. In sympathetic responses consisting of only one spike (single-spike responses), units with a lower threshold frequently appeared and units with a higher threshold joined mull-spike responses. The units with a short threshold R-R interval tended to have a long inhibitory latency from R wave, suggesting low conduction velocity. The correlation between firing probability and firing threshold and that between appearance in single-spike response and multi-spike response suggest a hierarchical manner of recruitment of vasoconstrictor units. For beat-to-beat responses, however, some deviation from the hierarchical recruitment was also observed.
Tsukahara
R
R
Institute for Developmental Research, Aichi Human Service Center, Japan.
Mano
T
T
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D004562:Electrocardiography; D004594:Electrophysiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000294:innervation*; D009474:Neurons / Q000502:physiology*; D011187:Posture / Q000502:physiology; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000166:cytology / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology*