Expression of tyrosine hydroxylase-like immunoreactivity in cell bodies in intraocular spinal cord grafts: a comparison with classical Falck-Hillarp histochemistry.
Earlier classical monoamine fluorescence histochemical and immunohistochemical studies describing the distribution of catecholamine neurons in the central nervous system led to the conclusion that all catecholamine fibre systems in the spinal cord have a supra-spinal origin. However, recent reports describing catecholamine neurons in upper cervical segments and at the lumbosacral junction have modified this picture. Isolated intraocular grafts of spinal cord offer a possible model with which to evaluate the presence of intrinsic monoamine neurons. Using immunohistochemistry with antiserum to tyrosine hydroxylase (TH) and Falck-Hillarp fluorescence histochemistry, such grafts from lower cervical segments were found to contain TH-immunoreactive perikarya. However, it was not possible to visualize cell bodies in grafts processed for fluorescence histochemistry. These findings raise questions about the sensitivity of the monoamine fluorescence histochemical method, and about the specificity of TH-immunohistochemistry. Perhaps TH-positive, catecholamine-negative neurons are more common than previously held or alternatively, TH expression in non-catecholamine neurons is induced by perturbations such as grafting brain tissue.
Henschen
A
A
Department of Histology and Neurobiology, Karolinska Institute, Stockholm, Sweden.
Goldstein
M
M
D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D005123:Eye; D005260:Female; D006651:Histocytochemistry; D007150:Immunohistochemistry; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism / Q000637:transplantation*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase