S. Soinila et al., NITRIC-OXIDE SYNTHASE IN THE AUTONOMIC AND SENSORY GANGLIA INNERVATING THE SUBMANDIBULAR SALIVARY-GLAND, Microscopy research and technique, 35(1), 1996, pp. 32-43
This article reviews the neuroanatomical studies on the distribution o
f nitric oxide synthase (NOS) in neurons and nerve fibers innervating
the submandibular gland. Specificity of NADPH-diaphorase activity as a
histochemical marker of neuronal NOS is discussed in light of corresp
onding NOS immunoreactivity. Anatomical data suggest that nitric oxide
may affect neural regulation of the submandibular gland through both
sympathetic, parasympathetic and sensory divisions of the autonomic ne
rvous system. NOS-containing nerve terminals in the gland parenchyme a
re mainly vascular and either parasympathetic and/or sensory in nature
, while sympathetic terminals lack NOS. Most postganglionic parasympat
hetic neurons are intensely NOS-immunoreactive. Some of the preganglio
nic parasympathetic neurons show vague reactivity, while their termina
ls in the submandibular ganglia stain heavily. The postganglionic symp
athetic neurons normally show only barely visible reactivity, while ma
nipulations interrupting axonal continuity increase neuronal NOS conte
nt. A subpopulation of the preganglionic sympathetic neurons and their
terminals are intensely reactive. The observations summarized here su
ggest that nitric oxide participates in the control of blood flow thro
ugh the gland, while direct effect on secretion is unlikely. (C) 1996
Wiley-Liss, Inc.