IMMUNOCYTOCHEMICAL LOCALIZATION OF MUSCARINIC M2 RECEPTOR IN THE RAT SPINAL-CORD

Muscarinic receptors have been implied in the regulation of spinal cor d functions. The m2 subtype has been found to be one of the major musc arinic receptors expressed in the spinal cord. In order to determine t he precise cellular localization of m2 receptor in the rat spinal cord , immunocytochemistry was performed using a commercially available spe cific antibody. In the dorsal horn, strong m2 immunoreactivity was det ected in the substantia gelatinosa. In the ventral horn, m2 immunoreac tivity was detected in patches that were associated with cell groups o f motor neurons. At higher magnification, m2 immunoreactivity was dete cted in neuronal processes and many of them were seen in close apposit ion to m2-negative perikarya and proximal dendrites of motor neurons. These results indicate that m2 receptor immunoreactivity is localized in different neuronal elements of the spinal cord. (C) 1997 Elsevier S cience Ireland Ltd.