Relationship of substance P to afferent characteristics of dorsal root ganglion neurones in guinea‐pig

Journal of Physiology - Tập 505 Số 1 - Trang 177-191 - 1997
Sally N. Lawson1, B. A. Crepps2, Edward R. Perl2
1Department of Physiology Medical School University Walk Bristol BS8 1TD, UK
2Department of Physiology, University of North Carolina Chapel Hill, North Carolina 27599–7545, USA

Tóm tắt

The relationship between the afferent properties and substance P‐like immunoreactivity (SP‐LI) of L6 and SI dorsal root ganglion (DRG) neuronal somata was examined in anaesthetized guinea‐pigs. Glass pipette microelectrodes filled with fluorescent dyes were used to make intracellular recordings and to label DRG somata. The dorsal root conduction velocity (CV) and the afferent receptive properties of each unit were categorized according to criteria established in other species. Categories included a variety of low threshold mechanoreceptive classes, innocuous thermoreceptive and several nociceptive classes. Nociceptive units were further subdivided on the basis of CV and the locus of the receptive field (superficial cutaneous, deep cutaneous or subcutaneous). SP‐LI was determined using the avidin–biotin complex method and the relative staining intensity determined by image analysis. The possible significance of labelling intensity is discussed. Clear SP‐LI appeared in twenty‐nine of 117 dye‐labelled neurones. All SP‐LI positive units with identified receptive properties were nociceptive but not all categories of nociceptors were positive. The intensity of SP‐LI labelling varied, often systematically, in relation to afferent properties. There was a tendency for nociceptive neurones with slower CVs and/or smaller cell bodies to show SP‐LI. Nineteen of fifty‐one C fibre neurones showed SP‐LI. Fewer than half the C polymodal nociceptors (CPMs) were positive. The most intensely labelled units were the deep cutaneous nociceptors and some of the CPMs in glabrous skin. C low threshold mechanoreceptors and cooling‐sensitive units did not show SP‐LI. Ten of sixty‐six A fibre neurones exhibited SP‐LI, including eight of sixteen Aδ nociceptors and two of fifteen Aα/β nociceptors. A fibre neurones exhibiting SP‐LI included seven of eight deep cutaneous mechanical nociceptors and some superficial cutaneous mechano‐heat nociceptors of hairy skin. In contrast, none of twenty superficial cutaneous A high threshold mechanoreceptor units or the thirty‐five A fibre low threshold units (D‐hair and other units) showed detectable SP‐LI. We conclude that SP‐LI labelling in guinea‐pig DRG neurones is related to (a) afferent receptive properties, (b) the tissue in which the peripheral receptive terminals are located, (c) the CV and (d) the soma size.

Từ khóa


Tài liệu tham khảo

10.1152/jn.1971.34.1.116

10.1152/jn.1969.32.6.1025

10.1016/0306-4522(92)90178-5

10.1113/jphysiol.1967.sp008227

10.1007/978-3-642-65438-1_3

10.1016/0006-8993(88)90771-8

10.1113/jphysiol.1985.sp015573

10.1007/BF00586896

10.1126/science.242075

10.1111/1523-1747.ep12497887

10.1016/0306-4522(89)90369-2

Lawson S. N., 1992, Sensory Neurones: Diversity, Development and Plasticity, 27

Lawson S. N., 1993, Differential correlation of substance P‐like immunoreactivity (SP‐LI) with the type of C‐fibre sensory receptor, Society for Neuroscience Abstracts, 19, 136.6

Lawson S. N., 1994, Substance P‐like immunoreactivity (SP‐LI) in guinea‐pig dorsal root ganglia (DRGs) is related to sensory receptor type in A and C fibre neurons, Journal of Physiology, 476, 39P

Lawson S. N., 1996, Methodological considerations in studies of correlations between peptide content and sensory receptor properties in dorsal root ganglion (DRG) neurones, Journal of Physiology, 491, 16S

10.1016/0304-3940(85)90252-6

10.1111/j.1476-5381.1992.tb09013.x

10.1016/0306-4522(89)90019-5

10.1016/0306-4522(89)90096-1

10.1152/physrev.1993.73.2.229

10.1016/0306-4522(91)90395-5

Shea V. K., 1985, Sensory receptors with unmyelinated (C) fibres innervating the skin of the rabbit's ear, Journal of Neurophysiology, 54, 491, 10.1152/jn.1985.54.3.491

10.1038/216173a0

Tiseo P. J., 1990, Differential release of substance P and somatostatin in the rat spinal cord in response to noxious cold and heat; effect of dynorphin A(1‐17), Journal of Pharmacology and Experimental Therapeutics, 252, 539

10.1016/0306-4522(89)90152-8

Thông tin
Thông tin xuất bản

Journal of Physiology

Tập 505 Số 1

177-191

Thông tin tác giả