LOCAL EFFECT OF PH CHANGES IN CEREBROSPINAL-FLUID ON VENTROLATERAL AREAS OF MEDULLA OBLONGATA AND ON SPINAL-CORD SURFACE ON ACTIVITY OF CARDIAC AND VERTEBRAL SYMPATHETIC-NERVES

  • 1 January 1976
    • journal article
    • research article
    • Vol. 27  (1) , 9-17
Abstract
Application of acid cerebrospinal fluid at pH 6.8 to the ventral surface of the [cat] medulla oblongata increased the arterial blood pressure and the activity of the vertebral nerve and enhanced respiratory modulation of the vertebral and cardiac nerves. Alkaline cerebrospinal fluid at pH 7.7 applied to the ventral surface of the medulla oblongata increased the arterial blood pressure without changes in the sympathetic nerve activity. When the spinal cord was superfused with artificial acid cerebrospinal fluid at the T1 level the activity of the vertebral nerve and cardiac nerve increased and the arterial blood pressure rose. The activity of sympathetic neurons in the medulla and spinal cord may be regulated by direct action of pH and CO2 tension on the neurons, or through an indirect effect mediated by superficial chemoreceptros of the medulla oblongata. The role of local changes of the brain blood flow was also discussed.