Time-dependent inhibition of hindlimb somatic afferent inputs to nucleus tractus solitarius. 1994

G M Toney, and S W Mifflin
Department of Pharmacology, University of Texas Health Science Center at San Antonio 78284-7764.

1. In the present investigation, experiments were performed in anesthetized, paralyzed rats (n = 40) to 1) identify and characterize responses of nucleus tractus solitarius (NTS) neurons to hindlimb somatic afferent inputs; 2) determine if hindlimb somatic inputs to NTS undergo time-dependent inhibition similar to that observed among visceral afferent inputs; and 3) determine if somatic afferent-evoked NTS unit discharge is altered by activation of baroreceptor afferent inputs. 2. Extracellular discharge was recorded from single NTS units following electrical stimulation (approximately 500 microA) of the contralateral tibial nerve (TN) (skeletal muscle afferents), sural nerve (SN) (cutaneous afferents), and the ipsilateral aortic nerve (AN) (baroreceptor afferents). To identify possible time-dependent interactions, a paired pulse or conditioning-test stimulation procedure was employed. The activity of NTS neurons was recorded in response to test stimuli delivered to either TN or SN first in the absence and then in the presence of conditioning stimuli delivered to TN, SN, or AN 50, 150, and 250 ms before the test stimuli. 3. The results indicate that among 31 NTS cells activated by somatic nerve stimulation, 14 (approximately 50%) received convergent inputs from both the TN and SN, 9 responded to TN stimulation only and 2 were activated by SN stimulation only. These cells were not spontaneously active but showed two distinct patterns of evoked discharge. Some had only a short latency, unimodal response that averaged 25.5 +/- 2.0 (SE) ms for TN inputs (n = 21) and 27.9 +/- 2.8 ms for SN inputs (n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

UI MeSH Term Description Entries
D007839 Functional Laterality Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot. Ambidexterity,Behavioral Laterality,Handedness,Laterality of Motor Control,Mirror Writing,Laterality, Behavioral,Laterality, Functional,Mirror Writings,Motor Control Laterality,Writing, Mirror,Writings, Mirror
D008297 Male Males
D009433 Neural Inhibition The function of opposing or restraining the excitation of neurons or their target excitable cells. Inhibition, Neural
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011311 Pressoreceptors Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls. Baroreceptors,Receptors, Stretch, Arterial,Receptors, Stretch, Vascular,Stretch Receptors, Arterial,Stretch Receptors, Vascular,Arterial Stretch Receptor,Arterial Stretch Receptors,Baroreceptor,Pressoreceptor,Receptor, Arterial Stretch,Receptor, Vascular Stretch,Receptors, Arterial Stretch,Receptors, Vascular Stretch,Stretch Receptor, Arterial,Stretch Receptor, Vascular,Vascular Stretch Receptor,Vascular Stretch Receptors
D011930 Reaction Time The time from the onset of a stimulus until a response is observed. Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D001931 Brain Mapping Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures. Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
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
D000200 Action Potentials Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli. Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000344 Afferent Pathways Nerve structures through which impulses are conducted from a peripheral part toward a nerve center. Afferent Pathway,Pathway, Afferent,Pathways, Afferent

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