Calcitonin gene-related peptide immunoreactivity in the trigeminal ganglion of Trimeresurus flavoviridis.
Crotaline snakes, which have infrared-sensitive pit organs, provide a good model for linking neuron morphology with sensory modality. In the trigeminal ganglion of the habu, Trimeresurus flavoviridis, cells positive for calcitonin gene-related peptide-like (CGRP) immunoreactivity were found to be of two types, darkly stained and lightly stained. They were pseudo-unipolar, having an axon divided into stem, peripheral branch, and central branch, all of which were 1 micron or less in diameter. Other, CGRP-negative cells in the ganglion were also pseudo-unipolar, but much larger. In configuration, some of the positive cells were similar to the neurons with A-delta fibers, and others to the neurons with C fibers that have been reported by other workers. On the basis of their distribution and density, and physiological studies by other workers, the CGRP-positive cells were judged to be not part of the infrared-receptive system, but to be involved in the transmission of nociception in small fibers.
D000818:Animals; D002116:Calcitonin / Q000235:genetics* / Q000276:immunology*; D002452:Cell Count; D048429:Cell Size; D007150:Immunohistochemistry; D008959:Models, Neurological; D009412:Nerve Fibers / Q000502:physiology; D010455:Peptides / Q000235:genetics* / Q000276:immunology; D012911:Snakes / Q000276:immunology*; D014276:Trigeminal Nerve / Q000276:immunology*
D010455:Peptides; D002116:Calcitonin