Elsevier

Experimental Neurology

Volume 85, Issue 3, September 1984, Pages 597-619
Experimental Neurology

Viscerosomatic convergence onto T2–T4 spinoreticular, spinoreticular-spinothalamic, and spinothalamic tract neurons in the cat

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Abstract

Neurons of T2 to T4 spinal segments were antidromically activated from the medullary reticular formation and the contralateral region in or near the ventral posterior lateral nucleus of the thalamus. Sixty-seven percent of the spinoreticular neurons projected to the ipsilateral, contralateral, or both ipsilateral and contralateral medullary reticular formation. In addition, 21% of the cells projected to the reticular formation and thalamus and 12% projected only to the thalamus. These cells received both visceral and somatic inputs. Electrical stimulation of cardiopulmonary sympathetic afferent fibers elicited an early peak of cell activity in 30 cells, an early and late peak in 38 cells, and only a late peak in 1 cell. Seventy-one percent of the cells had simple somatic receptive fields; these fields were localized to the left forelimb and left upper thorax. The remaining 29% of the cells had complex receptive fields that often extended to the hind limb as well as bilaterally. Classification of all cells according to threshold for activation of the somatic receptive field showed that 86% of the cells were high-threshold, 10% were wide dynamic range, and 4% were high-threshold but, in addition, were inhibited during hair movement. Viscerosomatic convergence onto these cells support Ruch's convergence projection theory for referred pain. These projecting neurons may be involved with referred pain associated with angina pectoris. In addition, they may also be involved with cardiovascular adjustments.

References (72)

  • J.W. Roughgarden

    Circulatory changes associated with spontaneous angina pectoris

    Am. J. Med.

    (1966)
  • D.L. Trevino et al.

    Location of cells of origin of the spinothalamic tract in the lumbar enlargement of the cat

    Exp. Neurol.

    (1972)
  • R.N. Weber et al.

    Effects of cardiac administration of bradykinin on thoracic spinal neurons in the cat

    Exp. Neurol.

    (1982)
  • F.P. Zemlan et al.

    Ascending tracts of the lateral columns of the rat spinal cord: a study using the silver impregnation and horseradish peroxidase techniques

    Exp. Neurol.

    (1978)
  • R.S. Alexander

    Tonic and reflex functions of medullary sympathetic cardiovascular centers

    J. Neurophysiol.

    (1946)
  • J.A. Andrezik et al.

    The nucleus paragigantocellularis lateralis in the rat

    Anat. Embryol.

    (1981)
  • D.G. Baker et al.

    Search for a cardiac nociceptor: stimulation by bradykinin of sympathetic afferent nerve endings in the heart of the cat

    J. Physiol. (London)

    (1980)
  • S.M. Barman et al.

    Sequence of activation of ventrolateral and dorsal medullary sympathetic neurons

    Am. J. Physiol.

    (1983)
  • A.L. Berman
  • R.W. Blair

    Responses of reticular formation neurons to epicardial bradykinin

    Physiologist

    (1983)
  • R.W. Blair et al.

    Responses of thoracic spinothalamic and spinoreticular cells to coronary artery occlusion

    J. Neurophysiol.

    (1984)
  • R.W. Blair et al.

    Characteristics of primate spinothalamic tract neurons receiving viscerosomatic convergent inputs in T3-T5 segments

    J. Neurophysiol.

    (1981)
  • R.W. Blair et al.

    Responses of thoracic spinothalamic neurons to intracardiac injection of bradykinin in the monkey

    Circ. Res.

    (1982)
  • R.W. Blair et al.

    Responses of spinoreticular and spinothalamic cells to intracardiac bradykinin

    Am. J. Physiol.

    (1984)
  • J. Boivie

    An anatomical reinvestigation of the termination of the spinothalamic tract in the monkey

    J. Comp. Neurol.

    (1979)
  • D. Bowsher

    Termination of the central pain pathway in man: the conscious appreciation of pain

    Brain

    (1957)
  • D. Bowsher et al.

    The gigantocellular reticular region and its spinal afferents: a light and electron microscope study in the cat

    J. Anat.

    (1970)
  • A.M. Brown

    Excitation of afferent cardiac sympathetic fibres during myocardial ischaemia

    J. Physiol. (London)

    (1967)
  • A.M. Brown et al.

    Spinal sympathetic reflexes initiated by coronary receptors

    J. Physiol. (London)

    (1971)
  • H. Burton et al.

    Spinothalamic projections in cat, raccoon and monkey: a study based on anterograde transport of horseradish peroxidase

  • E. Carstens et al.

    Laminar origins of spinothalamic projections in the cat as determined by the retrograde transport of horseradish peroxidase

    J. Comp. Neurol.

    (1978)
  • R. Casati et al.

    Afferent sympathetic unmyelinated fibres with left ventricular endings in the cat

    J. Physiol. (London)

    (1979)
  • F. Cervero

    Somatic and visceral inputs to the thoracic spinal cord of the cat: effects of noxious stimulation of the biliary system

    J. Physiol. (London)

    (1983)
  • J.M. Chung et al.

    Excitation of primate spinothalamic neurons by cutaneous C-fiber volleys

    J. Neurophysiol.

    (1979)
  • H. Cohen

    The mechanisms of visceral pain

    Trans. Med. Soc. London

    (1944)
  • P.N. Dilley et al.

    Cells of origin of the spinothalamic tract in the cat and rat

    Exp. Neurol.

    (1968)
  • Cited by (0)

    2

    R.D.F. is the recipient of a Research Career Development Award (HL00557) from the National Heart, Lung and Blood Institute.

    1

    We appreciate the technical assistance of Mary Martindale and Diana Holston. We also thank Tammi Williams for preparing the figures and Lula Campbell for typing the manuscript. This work was supported by National Institutes of Health grant HL22732. R.W.B. was supported by NIH Postdoctoral Fellowship HL06318 and R.N.W. was supported by Predoctoral Fellowship HL07430.

    3

    The current address of R.N.W. is School of Pharmacy, Southwestern Oklahoma State University, Weatherford, OK 73096.

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