Substance P-like immunoreactive nerves in the human eye
R. A. Stone and Y. Kuwayama
Using immunohistochemical methods, substance P is localized to nerves of
the human eye. Immunoreactive nerve fibers occur in the cornea, about
limbal blood vessels, and within the trabecular meshwork. Substance P-like
immunoreactive nerve fibers surround uveal blood vessels, especially in the
choroid and ciliary body. Immunoreactive nerves are seen in ciliary
processes. The ciliary muscle is innervated, as are the iris dilator and
sphincter muscles. Apposition of immunoreactive nerves to uveal melanocytes
is apparent. The distribution of substance P-like immunoreactive nerves in
the human eye parallels that found in other mammals. While substance P
probably has important neurotransmitter or neuromodulator roles in the eye,
further physiologic studies are required to define its ocular function.
