SUPRAMEDULLARY MODULATION OF SYMPATHETIC VASOMOTOR FUNCTION

Proceedings of the Australian Physiological and Pharmacological Society Symposium: Central Autonomic Regulation

Authors

  • Anthony JM Verberne,

    Corresponding author
    1. University of Melbourne, Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia
      University of Melbourne, Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin & Repatriation Medical Centre, Heidelberg, Victoria 3084, Australia. Email: (tonyv@austin.unimelb.edu.au)
    Search for more papers by this author
  • William Lam,

    1. University of Melbourne, Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia
    Search for more papers by this author
  • Neil C. Owens,

    1. University of Melbourne, Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia
    Search for more papers by this author
  • Daniela Sartor

    1. University of Melbourne, Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia
    Search for more papers by this author

University of Melbourne, Department of Medicine, Clinical Pharmacology and Therapeutics Unit, Austin & Repatriation Medical Centre, Heidelberg, Victoria 3084, Australia. Email: (tonyv@austin.unimelb.edu.au)

SUMMARY

1. Supramedullary structures including the ventral medial prefrontal cortex (MPFC) and the midbrain cuneiform nucleus (CnF) project directly and indirectly to premotor sympatho-excitatory neurons of the rostral ventrolateral medulla (RVLM) that are critically involved in the generation of sympathetic vasomotor tone.

2. Electrophysiological studies have demonstrated that activation of depressor sites within the MPFC is associated with splanchnic sympathetic vasomotor inhibition and inhibition of the activity of RVLM sympathoexcitatory neurons.

3. Antidromic mapping and anatomical studies support the notion that a relay in the nucleus tractus solitarius is involved in the cardiovascular response to MPFC stimulation.

4. The midbrain CnF, which lies adjacent to the midbrain periaqueductal grey, is a sympathoexcitatory region of the midbrain reticular formation. Sympathoexcitatory responses evoked from the CnF are associated with short-latency excitation of RVLM neurons.

5. Cuneiform nucleus stimulation induces the expression of mRNA for the immediate early genes c-fos and NGFI-A in midbrain, pontine and hypothalamic structures.

6. The MPFC and CnF are supramedullary structures with opposing modulatory influences on sympathetic vasomotor drive, whose roles in cardiovascular control mechanisms warrant further investigation.

Ancillary