Biomaterial Database

Receptive properties of embryonic chick sensory neurons innervating skin. 1997

M Koltzenburg, and G R Lewin

Department of Neurology, University of Würzburg, D-97080 Würzburg.

Receptive properties of embryonic chick sensory neurons innervating skin. J. Neurophysiol. 78: 2560-2568, 1997. We describe a new in vitro skin-nerve preparation from chick embryos that allows detailed study of the functional properties of developing sensory neurons innervating skin. Functionally single sensory afferents were isolated by recording from their axons in microdissected filaments of the cutaneous femoralis medialis nerve, which innervates skin of the thigh. A total of 157 single neurons were characterized from embryos [embryonic days 17-21 (E17-E21), n = 115] and hatchlings up to 3 wk old (n = 42). Neurons were initially classified on the basis of their conduction velocity; those conducting below 1.0 m/s were being classified as C fibers and faster conducting fibers as A fibers. The proportions of A and C fibers encountered in embryonic and hatchling preparations were not very different, indicating that myelination and axon growth proceeds quite slowly over the period studied. Afferent fibers that could subserve nociceptive and nonnociceptive functions were identified in the time period studied. Subpopulations of low-threshold myelinated afferent units exhibited rapidly or slowly adapting discharges to constant force stimuli and could have tactile functions. Many afferent fibers responded to noxious heat and were excited and sensitized by exposure to inflammatory mediators, suggesting that they are nociceptors. The behavior of these units changed in several respects over the period studied. The discharge of C fibers to noxious heat increased with age as did their mechanical thresholds. A substantial population of heat-responsive neurons (34% of the A fibers) present in embryos were not encountered in hatchling chicks. This indicates that substantial changes in the physiological response properties of sensory afferents occur after hatching. We conclude that this new preparation can be used for quantitative assessment of the receptive properties of developing sensory neurons and has considerable potential for the investigation of factors, such as neurotrophins, that specify and influence the functional phenotype of sensory neurons during embryonic development in vivo.

UI	MeSH Term	Description	Entries
D007249	Inflammation	A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.	Innate Inflammatory Response,Inflammations,Inflammatory Response, Innate,Innate Inflammatory Responses
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
D009413	Nerve Fibers, Myelinated	A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.	A Fibers,B Fibers,Fiber, Myelinated Nerve,Fibers, Myelinated Nerve,Myelinated Nerve Fiber,Myelinated Nerve Fibers,Nerve Fiber, Myelinated
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
D010812	Physical Stimulation	Act of eliciting a response from a person or organism through physical contact.	Stimulation, Physical,Physical Stimulations,Stimulations, Physical
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
D002642	Chick Embryo	The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.	Embryo, Chick,Chick Embryos,Embryos, Chick
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical