Biomaterial Database

Parallel nociceptive reflex pathways with negative and positive feedback functions to foot extensors in the cat. 2001

E D Schomburg, and H Steffens, and N Wada

Institute of Physiology, University of Göttingen, D-37073 Göttingen, Germany. eds@neuro-physiol.med.uni-goettingen.de

1. Nociceptive reflex pathways to foot extensors were investigated with particular attention given to those not following a flexor reflex (FRA) or withdrawal pattern. 2. In anaemically decapitated, high spinal paralysed cats nociceptive afferents of the foot pad were activated by noxious radiant heat (48-60 degrees C), while for comparison non-nociceptive afferents were activated by weak mechanical stimulation of the skin or graded electrical nerve stimulation. The reflex action of the afferents on hindlimb motoneurones, innervating plantaris and intrinsic foot extensors (tibial nerve), was investigated by intracellular recording, by monosynaptic reflex testing and by recording of neurograms during fictive locomotion. A possible descending control of the nociceptive and non-nociceptive pathways was tested by application of opioidergic and monoaminergic compounds. 3. Beside the typical FRA pattern evoked in the majority of hindlimb motoneurone pools by nociceptive afferents from different skin areas of the foot, the results revealed parallel excitatory and inhibitory nociceptive reflex pathways from the central pad and partly from the toe pads to foot extensors. The excitatory pathways, which did not follow the FRA pattern, were predominantly to plantaris and intrinsic foot extensors. They were distinctly less depressed by opioids and monoaminergic compounds than FRA pathways. 4. While the nociceptive FRA pathways have a general nocifensive withdrawal function, the nociceptive excitatory non-FRA pathway to the foot extensors causes a movement of the affected area towards the stimulus or at least a resistance against the stimulus, i.e. it mediates a positive feedback.

UI	MeSH Term	Description	Entries
D007980	Levodopa	The naturally occurring form of DIHYDROXYPHENYLALANINE and the immediate precursor of DOPAMINE. Unlike dopamine itself, it can be taken orally and crosses the blood-brain barrier. It is rapidly taken up by dopaminergic neurons and converted to DOPAMINE. It is used for the treatment of PARKINSONIAN DISORDERS and is usually given with agents that inhibit its conversion to dopamine outside of the central nervous system.	L-Dopa,3-Hydroxy-L-tyrosine,Dopaflex,Dopar,L-3,4-Dihydroxyphenylalanine,Larodopa,Levopa,3 Hydroxy L tyrosine,L 3,4 Dihydroxyphenylalanine,L Dopa
D008124	Locomotion	Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.	Locomotor Activity,Activities, Locomotor,Activity, Locomotor,Locomotor Activities
D008465	Mechanoreceptors	Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.	Golgi Tendon Organ,Golgi Tendon Organs,Krause's End Bulb,Krause's End Bulbs,Mechanoreceptor,Mechanoreceptor Cell,Meissner's Corpuscle,Neurotendinous Spindle,Neurotendinous Spindles,Receptors, Stretch,Ruffini's Corpuscle,Ruffini's Corpuscles,Stretch Receptor,Stretch Receptors,Mechanoreceptor Cells,Bulb, Krause's End,Bulbs, Krause's End,Cell, Mechanoreceptor,Cells, Mechanoreceptor,Corpuscle, Meissner's,Corpuscle, Ruffini's,Corpuscles, Ruffini's,End Bulb, Krause's,End Bulbs, Krause's,Krause End Bulb,Krause End Bulbs,Krauses End Bulb,Krauses End Bulbs,Meissner Corpuscle,Meissners Corpuscle,Organ, Golgi Tendon,Organs, Golgi Tendon,Receptor, Stretch,Ruffini Corpuscle,Ruffini Corpuscles,Ruffinis Corpuscle,Ruffinis Corpuscles,Spindle, Neurotendinous,Spindles, Neurotendinous,Tendon Organ, Golgi,Tendon Organs, Golgi
D008996	Monoamine Oxidase Inhibitors	A chemically heterogeneous group of drugs that have in common the ability to block oxidative deamination of naturally occurring monoamines. (From Gilman, et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p414)	MAO Inhibitor,MAO Inhibitors,Reversible Inhibitors of Monoamine Oxidase,Monoamine Oxidase Inhibitor,RIMA (Reversible Inhibitor of Monoamine Oxidase A),Reversible Inhibitor of Monoamine Oxidase,Inhibitor, MAO,Inhibitor, Monoamine Oxidase,Inhibitors, MAO,Inhibitors, Monoamine Oxidase
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
D009526	Nialamide	An MAO inhibitor that is used as an antidepressive agent.
D009619	Nociceptors	Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.	Pain Receptors,Receptors, Pain,Nociceptive Neurons,Neuron, Nociceptive,Neurons, Nociceptive,Nociceptive Neuron,Nociceptor,Pain Receptor
D010812	Physical Stimulation	Act of eliciting a response from a person or organism through physical contact.	Stimulation, Physical,Physical Stimulations,Stimulations, Physical
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat