The expression of bradykinin B(1) receptors on primary sensory neurones that give rise to small caliber sciatic nerve fibres in rats.
The bradykinin B(1) receptor has been considered as an important mediator for inflammatory pain. In the present study, we have investigated the fibre types of sciatic nerve primary sensory neurones that express B(1) receptors by retrograde tracing in combination with immunohistochemical staining, or double-immunohistochemical staining. Approximately 12% of the A-fibre dorsal root ganglion neurones, retrogradely labelled from an intra-sciatic nerve injection of fluorescein isothiocyanate-conjugated cholera toxin B subunit, were B(1) receptor-immunoreactive. Over 70% of the small diameter dorsal root ganglion neurones, retrogradely labelled from an intra-sciatic nerve injection of tetramethylrhodamine isothiocyanate-conjugated wheat germ agglutinin, were B(1) receptor-immunoreactive. Over 50% of the (predominantly non-peptidergic) C-fibre dorsal root ganglion neurones, retrogradely labelled from an intra-sciatic nerve injection of fluorescein isothiocyanate-conjugated Bandeiraea simplicifolia isolectin B4, were B(1) receptor-immunoreactive. When calcitonin gene-related peptide, which is contained mainly in small caliber C- and A(delta)-fibre primary afferents, and B(1) receptors were stained with a double-immunofluorescent method, over 80% of the calcitonin gene-related peptide-positive dorsal root ganglion neurones were B(1) receptor-immunoreactive. From these results we suggest that B(1) receptors are predominantly expressed by small diameter primary afferent neurones that give rise to sciatic nerve fibres, which include both peptidergic and non-peptidergic C-fibres and A(delta)-fibres. Since peripheral nociceptive information is primarily transmitted by C- and A(delta)-fibres, B(1) receptors may be involved in the modulation of nociceptive transduction or transmission.
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Department of Pharmacology, Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow CM20 2QR, UK. qingping_ma@merck.com
D000818:Animals; D000906:Antibodies; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis / Q000276:immunology; D048429:Cell Size; D002772:Cholera Toxin; D005727:Ganglia, Spinal / Q000166:cytology; D015870:Gene Expression / Q000502:physiology; D007150:Immunohistochemistry; D037102:Lectins; D009412:Nerve Fibers / Q000737:chemistry / Q000378:metabolism*; D009475:Neurons, Afferent / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D010146:Pain / Q000378:metabolism; D010446:Peptide Fragments; D037121:Plant Lectins; D051381:Rats; D017207:Rats, Sprague-Dawley; D043783:Receptor, Bradykinin B1; D018002:Receptors, Bradykinin / Q000032:analysis / Q000096:biosynthesis* / Q000276:immunology; D012584:Sciatic Nerve / Q000166:cytology*; D014909:Wheat Germ Agglutinins
D000906:Antibodies; C045475:Griffonia simplicifolia lectins; D037102:Lectins; D010446:Peptide Fragments; D037121:Plant Lectins; D043783:Receptor, Bradykinin B1; D018002:Receptors, Bradykinin; D014909:Wheat Germ Agglutinins; C084765:cholera toxin B subunit (50-75); D002772:Cholera Toxin; D015740:Calcitonin Gene-Related Peptide