Summary
-
1.
Reflex and spontaneous activity in cutaneous and muscle postganglionic neurones of the hind leg were investigated in 10 chloralose anaesthetized cats which were spinalized at Th8 7 to 96 days before the experiments. The reflexes were elicited by electrical stimulation of cutaneous Group II to Group IV afferent fibres in the sural nerve and by natural stimulation of hairs and of cutaneous nociceptors.
-
2.
Electrical stimulation of cutaneous afferent fibres elicited the same reflex pattern in both cutaneous and muscle postganglionic neurons. Group II fibres had — if any effects — mostly inhibitory effects on the postganglionic neurones. Stimulation of Group III and Group IV fibres induced excitation followed by a depression of the spontaneous activity in the postganglionic neurones.
-
3.
Natural stimulation of hairs by air jets induced depression of the spontaneous activity in both types of postganglionic neurones. Noxious mechanical or thermal stimuli to the skin induced excitation in both types of postganglionic neurones. The spontaneous activity in cutaneous postganglionic neurones could additionally be depressed by noxious stimuli applied to the skin area which is very close to the area innervated by these neurones.
-
4.
Reflexes and spontaneous activity recovered partially in cutaneous postganglionic neurones in about 10 weeks after spinalization. Those in muscle postganglionic neurones recovered partially after about 4 weeks. They were stronger in muscle postganglionic neurones than in cutaneous postganglionic neurones.
-
5.
The results are discussed in relation to the central organization of the sympathetic nervous system in the neuraxis and in relation to other investigations of the somato-sympathetic reflexes in spinal animals.
Similar content being viewed by others
References
Bayliss, W.M.: On the origin from the spinal cord of the vasodilator fibres of the hind-limb, and on the nature of these fibres. J. Physiol, (Lond.) 26, 173–209 (1901)
Beacham, W.S., Perl, E.R.: Background and reflex discharge of sympathetic preganglionic neurones in the spinal cat. J. Physiol. (Lond.) 172, 400–416 (1964a)
Beacham, W.S., Perl, E.R.: Characteristics of a spinal sympathetic reflex. J. Physiol. (Lond.) 173, 431–448 (1964b)
Brooks, C.McC.: Reflex activation of the sympathetic system in the spinal cat. Amer. J. Physiol. 106, 251–266 (1933)
Brooks, C.McC.: The reaction of chronic spinal animals to hemorrhage. Amer. J. Physiol. 114, 30–39 (1935)
Celander, O., Folkow, B.: The nature and the distribution of afferent fibres provided with the axon reflex arrangement. Acta physiol. scand. 29, 359–370 (1953)
Coote, J.H., Downman, C.B.B.: Central pathways of some autonomic reflex discharges. J. Physiol. (Lond.) 183, 714–729 (1966)
Coote, J.H., Downman, C.B.B., Weber, W.v.: Reflex discharges into thoracic white rami elicited by somatic and visceral afferent excitation. J. Physiol. (Lond.) 202, 147–159 (1969)
Coote, J.H., Perez-Gonzales, J.F.: The response of some sympathetic neurones to volleys in various afferent nerves. J. Physiol. (Lond.) 208, 261–278 (1970)
Fernandez de Molina, A., Perl, E.R.: Sympathetic activity and the systemic circulation in the spinal cat. J. Physiol. (Lond.) 181, 82–102 (1965)
Horeyseck, G., Jänig, W.: Response patterns in vasoconstrictors to the skin and muscle upon stimulation of skin receptors in chronic spinal cats. Pflügers Arch. 332, R 64 (1972)
Horeyseck, G., Jänig, W.: Somato-sympathetic reflexes in cutaneous and muscular sympathetic fibres in decerebrate cats. Pflügers Arch. 343, R 65 (1973)
Horeyseck, G., Jänig, W.: Reflexes in postganglionic fibres within skin and muscle nerves after mechanical non-noxious stimulation of skin. Exp. Brain Res. 20, 115–123 (1974a)
Horeyseck, G., Jänig, W.: Reflexes in postganglionic fibres within skin and muscle nerves after noxious stimulation of skin. Exp. Brain Res. 20, 125–134 (1974b)
Koizumi, K., Brooks, C.McC.: The integration of autonomic system reactions: a discussion of autonomic reflexes, their control and their association with somatic reactions. Ergebn. Physiol. 67, 1–68 (1972)
Koizumi, K., Sato, A.: Reflex activity of single sympathetic fibres to skeletal muscle produced by electrical stimulation of somatic and vago-depressor afferent nerves in the cat. Pflügers Arch. 332, 283–301 (1972)
Langley, J.N.: Vaso-motor centres. Part III. Spinal vascular (and other autonomic) reflexes and the effect of strychnine on them. J. Physiol. (Lond.) 59, 231–258 (1924)
Ladpli, R., Wang, G.H.: Spontaneous variations of skin potentials in footpads of normal, striatal and spinal cats. J. Neurophysiol. 23, 448–452 (1960)
Sahs, A.L., Fulton, J.F.: Somatic and autonomic reflexes in spinal monkeys. J. Neurophysiol. 3, 258–268 (1940)
Sato, A.: Spinal and medullary reflex components of the somato-sympathetic reflex discharges evoked by stimulation of the Group IV somatic afferents. Brain Res. 51, 307–318 (1973)
Sato, A., Schmidt, R.F.: Spinal and supraspinal components of the reflex discharges into lumbar und thoracic white rami. J. Physiol. (Lond.) 212, 839–850 (1971)
Sato, A., Schmidt, R.F.: Somato-sympathetic reflexes: afferent fibers, central pathways, discharge characteristics. Physiol. Rev. 53, 916–947 (1973)
Sato, A., Tsushima, N., Fujimori, B.: Reflex potentials of lumbar sympathetic trunk with sciatic nerve stimulation in cats. Jap. J. Physiol. 15, 532–539 (1965)
Schmidt, R.F., Weller, E.: Reflex activity in the cervical and lumbar sympathetic trunk induced by unmyelinated somatic afferents. Brain Res. 24, 207–218 (1970)
Sherrington, C.S.: Notes on temperature after spinal transection, with some observations on shivering. J. Physiol. (Lond.) 58, 405–414 (1924)
Wang, G.H.: The neural control of sweating. Madison: University of Wisconsin Press 1964
Author information
Authors and Affiliations
Additional information
Supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich Cardiovasculäres System.
Rights and permissions
About this article
Cite this article
Horeyseck, G., Jänig, W. Reflex activity in postganglionic fibres within skin and muscle nerves elicited by somatic stimuli in chronic spinal cats. Exp Brain Res 21, 155–168 (1974). https://doi.org/10.1007/BF00234387
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00234387