Biomaterial Database

Jendrassik maneuver facilitates soleus H-reflex without change in average soleus motoneuron pool membrane potential. 1988

R Dowman, and J R Wolpaw

Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201.

Facilitation of spinal reflex amplitude by remote muscle contraction, otherwise known as the Jendrassik maneuver (JM), was first shown over 100 years ago, yet the mechanism by which this facilitation operates remains undetermined. Earlier work has eliminated participation of the muscle spindle in JM-induced spinal reflex facilitation, leaving changes in postsynaptic (e.g., change in average soleus motoneuron membrane potential) and presynaptic (e.g., inhibition of presynaptic inhibition) mechanisms as viable candidates. We recorded background EMG in the soleus muscle during JM-induced soleus H-reflex facilitation in humans. The JM in this experiment consisted of wrist muscle contraction. Soleus background EMG was maintained by the subject at either a zero level (e.g., relaxed) or a specified moderate level prior to and during the JM. The JM increased H-reflex amplitude by comparable amounts in both situations, but had no effect on soleus background EMG. Given the well-known relationship between the average motoneuron pool membrane potential and background EMG, we conclude that JM facilitation of the soleus H-reflex is not caused by an increase in background excitatory input to the soleus motoneuron pool. Remaining candidates for mediation of JM induced H-reflex facilitation include change in stimulus-evoked afferent input at some point proximal to the muscle spindle, such as reduction in presynaptic inhibition, or a change in motoneuron input resistance.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D012026	Reflex, Stretch	Reflex contraction of a muscle in response to stretching, which stimulates muscle proprioceptors.	Reflex, Tendon,Stretch Reflex,Tendon Reflex
D004576	Electromyography	Recording of the changes in electric potential of muscle by means of surface or needle electrodes.	Electromyogram,Surface Electromyography,Electromyograms,Electromyographies,Electromyographies, Surface,Electromyography, Surface,Surface Electromyographies
D005260	Female		Females
D006181	H-Reflex	A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.	H Reflex,H-Reflexes,H Reflexes,Reflex, H
D006614	Hindlimb	Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)	Hindlimbs