Immunohistochemical localization of ciliary neurotrophic factor receptor alpha expression in the rat nervous system.

Ciliary neurotrophic factor receptor alpha (CNTFR alpha) is essential for normal embryonic development and may be involved in postnatal and adult neuronal maintenance. In addition, a rapidly growing body of evidence suggests that CNTFR alpha serves as a site of action for future growth factor therapeutics capable of treating a wide variety of disorders resulting from neuronal loss. We raised two polyclonal, anti-CNTFR alpha antisera against synthetic peptides corresponding to independent regions of rat CNTFR alpha. Western blot and immunohistochemical analyses indicated that affinity-purified preparations of both antisera specifically recognize CNTFR alpha. In the adult brain, the highest levels of CNTFR alpha immunoreactivity were found in the perikarya, dendrites and, occasionally, the axons of several distinct classes of neurons including hippocampal formation neurons, some sensory neurons, and many neurons involved in motor control. CNTFR alpha immunoreactivity also was concentrated in the following: perikarya, dendrites, and axons of ventral horn motor neurons in adult spinal cord; perikarya and axons of adult dorsal root ganglion neurons; and axons in adult peripheral nerve. In embryonic tissue, the highest levels of CNTFR alpha immunoreactivity were observed in differentiating neurons and their processes. Therefore, the present data suggest that CNTFR alpha serves several diverse functions in adulthood and during development.