title: Interactions between femoral venous afferents and lumbar spinal reflex pathways.
abstract: This study reports findings of spinal reflex connections of afferent fibers electrically excited in the wall of the femoral vein. Condition-test experiments, and EMG recordings revealed that the femoral venous afferents have facilitatory connections to flexor and extensor motoneurons of both the proximal and the distal hindlimb muscles. Femoral venous afferent stimulation which produced facilitation, also produced inhibition of the test reflexes following the facilitation. Because the inhibition was enhanced by diazepam injection and because the inhibitory time-course correlated closely to the time-courses of both dorsal root potentials and individual tests of primary afferent depolarization, the inhibition was suggested to be produced by presynaptic inhibition. The potentially significant role of the venous afferent connections in a reflex-elicited skeletal muscle pump or in an increase in intramuscular venous counterpressure is discussed.
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002415:Cats; D003975:Diazepam / Q000494:pharmacology; D004576:Electromyography; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D005268:Femoral Vein / Q000294:innervation*; D005727:Ganglia, Spinal / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D009132:Muscles / Q000294:innervation; D009431:Neural Conduction / Q000187:drug effects; D009433:Neural Inhibition / Q000187:drug effects; D012018:Reflex / Q000502:physiology*; D012023:Reflex, Monosynaptic / Q000187:drug effects; D012684:Sensory Thresholds; D013116:Spinal Cord / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000502:physiology; D013569:Synapses / Q000502:physiology
chemical_list: D003975:Diazepam