Cell type and conduction velocity of rat primary sensory neurons with calcitonin gene-related peptide-like immunoreactivity.
An immunocytochemical double labelling study of L4 dorsal root ganglia from rats aged seven to 10 weeks was made with an antibody to calcitonin gene-related peptide and with RT97, an anti-neurofilament antibody which specifically labels the light neuron population. Peptide immunoreactivity was found in an average of 46.5% of all neurons. Sixty-two per cent of the small dark (RT97-negative) and 30% of the light (RT97-positive) neuron populations contained the peptide. About one-third (32%) of the cells with peptide immunoreactivity were light cells and about two-thirds (68%) were small dark cells. Intracellular electrophysiological recordings were made in vitro from neurons in lumbar (L4, L5 and L6) dorsal root ganglia from six- to eight-week-old rats, followed by dye-injection and immunocytochemistry. This showed that conduction velocities of neurons with calcitonin gene-related peptide-like immunoreactivity ranged from 0.5 to 28.6 m/s. Seventy-three neurons were successfully processed. Of these, calcitonin gene-related peptide-like immunoreactivity was found in 46% of C-fibre neurons, 33% of A delta-fibre neurons and in 17% of the A alpha/beta-fibre neurons. The peptide-like immunoreactivity was found in approximately 25% of all A-fibre neurons sampled.
McCarthy
P W
PW
Department of Physiology, Medical School, University of Bristol, U.K.
Lawson
S N
SN
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D009431:Neural Conduction; D009475:Neurons, Afferent / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
D015740:Calcitonin Gene-Related Peptide