Biomaterial Database

Extracellular potassium accumulation in the frog spinal cord induced by stimulation of the skin and ventrolateral columns. 1981

G Czéh, and N Kríz, and E Syková

1. Changes in extracellular K(+) concentration (Delta[K](e)), dorsal root potentials (DRPs) and single unit activity were studied in the frog spinal cord in response to stimulation of the skin of the hindlimb by touch, pressure, hot water (heat), single electrical pulses and to stimulation of the ventrolateral columns (LC).2. Single electrical pulses, various types of adequate stimulation applied to the skin of the hind limb for 1-2 s as well as single volleys of LC led to a Delta[K](e) of up to 0.2 mmol.l(-1). Stimuli which evoked larger Delta[K](e) also produced larger DRPs in the same frog preparation.3. The briefest heat stimuli, which lasted about 1-2 s, led to more prolonged activity in dorsal horn interneurones than did a single volley or a single tactile stimulus and the Delta[K](e) were longer and larger and had a slower rise time.4. The ;slow' second component of dorsal root depolarization (presumably mediated by K(+)) was observed after electrical and heat stimulation of the skin on the hind limb corresponding to the time course of Delta[K](e).5. The maximum Delta[K](e) induced by nociceptive stimulation occurred in the grey matter of the dorsal horn at a depth of 300-600 mum from the dorsal surface. The maximum response to single stimuli applied to the skin occurred at a depth of 400-800 mum, while that evoked by LC stimulation in the ventral horn at a depth of 1000-1400 mum.6. Repetitive and more prolonged nociceptive stimulation (5-20 s) produced a Delta[K](e) of up to 1 mmol.l(-1). The Delta[K](e) in response to repetitive tactile stimulation does not exceed 0.2 mmol.l(-1). Repetitive stimulation (100 Hz) of LC fibres led to an increase in [K](e) of up to 9-10 mmol.l(-1) in the ventral horn; this level was similar to that achieved in the intermediate region by electrical repetitive stimulation of the skin (100 Hz). Tetanic stimulation of the ventral root led to a Delta[K](e) of only about 0.05 mmol.l(-1) at a depth of 500-700 mum and no measurable Delta[K](e) within the ventral horn.7. Spontaneous Delta[K](e) associated with spontaneous DRPs and VRPs were observed during the decay phase of Delta[K](e) at various intervals from several seconds to one minute after nociceptive or electrical stimulation of the skin, suggesting the occurrence of a longlasting increase in excitability.8. The depolarization of dorsal root fibres evoked by nociceptive stimulation, tetanic stimulation of the LC and single or tetanic stimulation of the skin was followed by a dorsal root hyperpolarization. Its size, as well as that of Delta[K](e), was dependent on the frequency and duration of stimulation and its time course correlated with the dissipation of Delta[K](e) when stimulation was discontinued.9. It is suggested that the extracellular K(+) accumulation could, under physiological conditions, contribute to the modulation of spinal cord transmission, acting both pre-and post-synaptically. Low levels of increased [K](e) were associated with facilitation of impulse transmission while higher increases could result in its inhibition.

UI	MeSH Term	Description	Entries
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
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011893	Rana esculenta	An edible species of the family Ranidae, occurring in Europe and used extensively in biomedical research. Commonly referred to as "edible frog".	Pelophylax esculentus
D011896	Rana temporaria	A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.	European Common Frog,Frog, Common European,Common European Frog,Common Frog, European,European Frog, Common,Frog, European Common
D005071	Evoked Potentials	Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.	Event Related Potential,Event-Related Potentials,Evoked Potential,N100 Evoked Potential,P50 Evoked Potential,N1 Wave,N100 Evoked Potentials,N2 Wave,N200 Evoked Potentials,N3 Wave,N300 Evoked Potentials,N4 Wave,N400 Evoked Potentials,P2 Wave,P200 Evoked Potentials,P50 Evoked Potentials,P50 Wave,P600 Evoked Potentials,Potentials, Event-Related,Event Related Potentials,Event-Related Potential,Evoked Potential, N100,Evoked Potential, N200,Evoked Potential, N300,Evoked Potential, N400,Evoked Potential, P200,Evoked Potential, P50,Evoked Potential, P600,Evoked Potentials, N100,Evoked Potentials, N200,Evoked Potentials, N300,Evoked Potentials, N400,Evoked Potentials, P200,Evoked Potentials, P50,Evoked Potentials, P600,N1 Waves,N2 Waves,N200 Evoked Potential,N3 Waves,N300 Evoked Potential,N4 Waves,N400 Evoked Potential,P2 Waves,P200 Evoked Potential,P50 Waves,P600 Evoked Potential,Potential, Event Related,Potential, Event-Related,Potential, Evoked,Potentials, Event Related,Potentials, Evoked,Potentials, N400 Evoked,Related Potential, Event,Related Potentials, Event,Wave, N1,Wave, N2,Wave, N3,Wave, N4,Wave, P2,Wave, P50,Waves, N1,Waves, N2,Waves, N3,Waves, N4,Waves, P2,Waves, P50
D005110	Extracellular Space	Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.	Intercellular Space,Extracellular Spaces,Intercellular Spaces,Space, Extracellular,Space, Intercellular,Spaces, Extracellular,Spaces, Intercellular
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012879	Skin Physiological Phenomena	The functions of the skin in the human and animal body. It includes the pigmentation of the skin.	Skin Physiological Processes,Skin Physiology,Physiology, Skin,Skin Physiological Concepts,Skin Physiological Phenomenon,Skin Physiological Process,Concept, Skin Physiological,Concepts, Skin Physiological,Phenomena, Skin Physiological,Phenomenas, Skin Physiological,Phenomenon, Skin Physiological,Phenomenons, Skin Physiological,Physiological Concept, Skin,Physiological Concepts, Skin,Physiological Phenomena, Skin,Physiological Phenomenas, Skin,Physiological Phenomenon, Skin,Physiological Phenomenons, Skin,Process, Skin Physiological,Processes, Skin Physiological,Skin Physiological Concept,Skin Physiological Phenomenas,Skin Physiological Phenomenons
D013116	Spinal Cord	A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.	Coccygeal Cord,Conus Medullaris,Conus Terminalis,Lumbar Cord,Medulla Spinalis,Myelon,Sacral Cord,Thoracic Cord,Coccygeal Cords,Conus Medullari,Conus Terminali,Cord, Coccygeal,Cord, Lumbar,Cord, Sacral,Cord, Spinal,Cord, Thoracic,Cords, Coccygeal,Cords, Lumbar,Cords, Sacral,Cords, Spinal,Cords, Thoracic,Lumbar Cords,Medulla Spinali,Medullari, Conus,Medullaris, Conus,Myelons,Sacral Cords,Spinal Cords,Spinali, Medulla,Spinalis, Medulla,Terminali, Conus,Terminalis, Conus,Thoracic Cords
D013126	Spinal Nerve Roots	Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.	Dorsal Roots,Spinal Roots,Ventral Roots,Dorsal Root,Nerve Root, Spinal,Nerve Roots, Spinal,Root, Dorsal,Root, Spinal,Root, Spinal Nerve,Root, Ventral,Roots, Dorsal,Roots, Spinal,Roots, Spinal Nerve,Roots, Ventral,Spinal Nerve Root,Spinal Root,Ventral Root