Lateral reticular regions and the descending control of dorsal horn neurones of the cat: selective inhibition by electrical stimulation.
In barbiturate-anaesthetized cats, brainstem sites were electrically stimulated while studying the synaptic responses of lumbar dorsal horn neurones. The excitation of these neurones by impulses in unmyelinated primary afferents was selectively inhibited by stimulation of the ventrolateral medulla in the region of the caudal lateral reticular nucleus. The significance of this inhibition was heightened by the finding that stimulus currents producing inhibition from this area were less effective in the raphé region and not effective at intervening or dorsal sites. Bilateral lesions of the inhibition-producing ventrolateral sites reduced tonic descending inhibition of the responses of dorsal horn neurones to impulses in C fibres. The lateral reticular regions of the medulla may thus exert a considerable control over the transmission of nociceptive information in the cat spinal cord.
D000818:Animals; D001931:Brain Mapping; D002415:Cats; D004525:Efferent Pathways / Q000502:physiology; D004558:Electric Stimulation; D005071:Evoked Potentials; D008636:Mesencephalon / Q000502:physiology; D009433:Neural Inhibition; D009475:Neurons, Afferent / Q000502:physiology; D011903:Raphe Nuclei / Q000502:physiology; D012154:Reticular Formation / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*