Fig. 16.

Discharge activities of sympathetic efferent fiber filaments (shown as peri- or post-stimulation activities) innervating epinephrine secreting cells (EPI ADR, upper panel) or nor-epinephrine secreting cells (NE ADR, lower panel) of the adrenal medulla. Right-hand diagrams identification according to response to tissue hypoglycemia (HYPOGLYCEMIA) induced by administration of 2-deoxy-glucose (2DG) which activates EPI ADR fibers and inhibits NE ADR fibers. Left-hand diagrams electrostimulation of the rostroventral lateral medulla (RVLM STIMULATION) at time 0, with peri-stimulus histograms showing delayed activation of fibers innervating EPI ADR cells which persists for ≈0.2 s after stimulation, while activity of fibers innervating NE ADR cells is increased instantaneously, though briefly, and subsequently depressed for >0.2 s after the end of stimulation. Middle diagrams with original recordings of fiber discharges (upper traces) show activity changes caused by stimulation of the aortic depressor nerve (ADN STIMULATION, bars below upper traces). With some delay activity of fibers innervating NE ADR cells is strongly reduced temporarily, while activity of fibers innervating EPI ADR cells does not change distinctly. The response pattern is reflected by the peri-stimulus histograms. From Morrison [54]