Re. Papka et al., NITRIC-OXIDE NERVES IN THE UTERUS ARE PARASYMPATHETIC, SENSORY, AND CONTAIN NEUROPEPTIDES, Cell and tissue research, 279(2), 1995, pp. 339-349
Nitric oxide (NO) is synthesized in neurons and is a potent relaxer of
vascular and nonvascular smooth muscle. The uterus contains abundant
NO-synthesizing nerves which could be autonomic and/or sensory. This s
tudy was undertaken to determine: 1) the source(s) of NO-synthesizing
nerves in the rat uterus and 2) what other neuropeptides or transmitte
r markers might coexist with NO in these nerves. Retrograde axonal tra
cing, utilizing Fluorogold injected into the uterine cervix, was emplo
yed for identifying sources of uterine-projecting neurons. NO-synthesi
zing nerves were visualized by staining for nicotinamide adenine dinuc
leotide phosphate (reduced)-diaphorase (NADPH-d) and immunostaining wi
th an antibody against neuronal/type I NO synthase (NOS). NADPH-d-posi
tive perikarya and terminal fibers were NOS-immunoreactive (-I). Some
NOS-I/NADPH-d-positive nerves in the uterus are parasympathetic and or
iginate from neurons in the pelvic paracervical ganglia (PG) and some
are sensory and originate from neurons in thoracic, lumbar, and sacral
dorsal root ganglia. No evidence for NOS-I/NADPH-d-positive sympathet
ic nerves in the uterus was obtained. Furthermore, double immunostaini
ng revealed that in parasympathetic neurons, NOS-I/NADPH-d-reactivity
coexists with vasoactive intestinal polypeptide, neuropeptide Y, and a
cetylcholinesterase and in sensory nerves, NOS-I/NADPH-d-reactivity co
exists with calcitonin generated peptide and substance P. In addition,
tyrosine hydroxylase(TH)-I neurons of the PG do not contain NOS-I/NAD
PH-d-reactivity, but some TH-I neurons are apposed by NOS-I varicositi
es. These results suggest NO-synthesizing nerves in the uterus are aut
onomic and sensory, and could play significant roles, possibly in conj
unction with other putative transmitter agents, in the control of uter
ine myometrium and vasculature.