Membrane Properties of Physiologically Classified Rat Dorsal Horn Neurons In Vitro: Correlation with Cutaneous Sensory Afferent Input

European Journal of Neuroscience - Tập 6 Số 6 - Trang 998-1007 - 1994
J.A. López‐García1, A.E. King2
1Department of Physiology, University of Leeds, UK.
2Dept. of Physiology, University of Leeds, Leeds LS2 9NQ, UK

Tóm tắt

AbstractDorsal horn neurons in the young rat spinal cord‐hindlimb preparation were physiologically classified as wide dynamic range (WDR), nociceptive specific (NS) or low threshold (LT) according to their excitatory responses to low and high intensity mechanical stimuli applied to the hindlimb skin. Two additional types were classified: neurons displaying only sub‐threshold excitations (SUB) and neurons displaying inhibitory events (INH), such as inhibitory post‐synaptic potentials or interruption of spontaneous spiking following cutaneous stimulation. Direct intracellular current injection revealed four different patterns of spiking behaviour: group A neurons were characterized by tonic firing in response to depolarizing current pulses; group B neurons were strongly phasic, producing only one spike at the beginning of the pulse; group A‐B neurons generated an early unsustained (< 300 ms) burst of spikes; and group C neurons exhibited anomalous rectification in response to hyperpolarizing current which was followed by a voltage‐dependent rebound excitation. A statistically significant (P≤ 0.01) association existed between a neuron's physiological classification and its electrophysiological profile. The majority of WDR neurons responded with tonic firing and were assigned to group A, while NS neurons were strongly represented in group A‐B. All INH neurons were assigned to group C. LT neurons were distributed between groups A and A‐B, and SUB neurons were distributed between groups A and B. These data indicate, firstly, that dorsal horn neurons possess heterogeneous membrane properties and, secondly, that a relationship exists between a neuron's biophysical profile and its excitatory or inhibitory response to peripheral cutaneous afferent stimulation. The implications for dorsal horn somatosensory processing are discussed.

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Tài liệu tham khảo

Bellmonte C., 1983, Membrane properties of cat sensory neurones with chemoreceptor and baroreceptor endings, J. Physiol. (Lond.), 342, 603, 10.1113/jphysiol.1983.sp014871

10.1113/jphysiol.1981.sp013970

10.1007/BF00239031

Brown A. G., 1987, Excitatory actions of single impulses in single hair follicle afferent fibres on single spinocervical tract cells in cat, J. Physiol. (Lond.), 382, 291, 10.1113/jphysiol.1987.sp016368

10.1113/jphysiol.1982.sp014062

10.1007/978-1-4684-4994-5_9

10.1113/expphysiol.1979.sp002484

10.1038/347765a0

10.1016/0006-8993(87)91493-4

Connors J. A., 1971, Voltage clamp studies of a transient outward membrane current in gastropod neural somata, J. Physiol. (Lond.), 213, 21, 10.1113/jphysiol.1971.sp009365

10.1016/0301-0082(89)90003-8

10.1113/jphysiol.1985.sp015725

Forsythe I. D., 1993, The binaural auditory pathway: membrane currents limiting multiple action potential generation in the rat medial nucleus of the trapezoid body, Proc. R. Soc. Lond., 251, 142

10.1038/305805a0

Hounsgaard J., 1988, Response properties of the motoneurones in a slice preparation of the turtle spinal cord, J. Physiol. (Lond.), 389, 575, 10.1113/jphysiol.1988.sp017058

10.1016/0006-8993(91)90630-E

King A. E., 1990, Activation of dorsal horn neurones by natural activation of cutaneous afferents in the rat spinal cord‐hindlimb preparation, Eur. J. Neurosci., 3158

10.1016/0306-4522(88)90233-3

10.1016/0165-0270(90)90092-T

10.1126/science.3059497

Lopez‐Garcia J. A., 1992, The role of amino acid receptor subtypes in synaptic transmission from cutaneous afferents onto rat dorsal horn neurones in vitro, J. Physiol. (Lond.), 459, 219P

Lopez‐Garcia J. A., 1993, Electrophysiological properties of rat dorsal horn neurons which receive nociceptive inputs, Eur. J. Neurosci., S6

10.1113/jphysiol.1984.sp015378

10.1016/0304-3940(87)90267-9

10.1016/0014-4886(66)90068-9

10.1113/jphysiol.1983.sp014485

10.1113/jphysiol.1984.sp015017

10.1016/0014-4886(71)90022-7

Schwindt P. C, 1988, Influence of anomalous rectifier activation on afterhyperpolarizations of neurons from cat sensorimotor cortex in vitro, J. Neurophysiol., 59, 468, 10.1152/jn.1988.59.2.468

10.1523/JNEUROSCI.04-02-00604.1984

10.1016/0306-4522(92)90428-5

10.1016/0014-4886(88)90158-6

10.1111/j.1460-9568.1989.tb00354.x

10.1007/978-1-4899-0597-0

10.1002/cne.902210307

10.1152/jn.1989.62.4.907

10.1152/jn.1989.62.1.109

Zhang D., 1991, Intracellular study of electrophysiological features of primate spinothalamic tract neurones and their responses to afferent inputs, J. Neurophysiol., 65, 1554, 10.1152/jn.1991.65.6.1554

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European Journal of Neuroscience

Tập 6 Số 6

998-1007

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