Localization of NADPH diaphorase in the lumbosacral spinal cord and dorsal root ganglia of the cat

Abstract

The distribution of NADPH-d activity in the spinal cord and dorsal root ganglia of the cat was studied to evaluate the role of nitric oxide in lumbosacral afferent and spinal autonomic pathways. At all levels of the spinal cord NADPH-d staining was present in neurons and fibers in the superficial dorsal horn and in neurons around the central canal and in the dorsal commissure. In addition, the sympathetic autonomic nucleus in the rostral lumbar segments exhibited prominent NADPH-d cellular staining whereas the parasympathetic nucleus in the sacral segments was not well stained. The most prominent NADPH-d activity in the sacral segments occurred in fibers extending from Lissauer's tract through laminae I along the lateral edge of the dorsal horn to lamina V and the region of the sacral parasympathetic nucleus. These fibers were very similar to VIP-containing and pelvic nerve afferent projections in the same region. They were prominent in the S1-S3 segments but not in adjacent segments (L6-L7 and Cx1) or in thoracolumbar and cervical segments. NADPH-d activity and VIP immunoreactivity in Lissauer's tract and the lateral dorsal horn were eliminated or greatly reduced after dorsal-ventral rhizotomy (S1-S3), indicating the fibers represent primary afferent projections. A population of small diameter afferent neurons in the L7-S2 dorsal root ganglia were intensely stained for NADPH-d. The functional significance of the NADPH-d histochemical stain remains to be determined; however, if NADPH-d is nitric oxide synthase then this would suggest that nitric oxide may function as a transmitter in thoracolumbar sympathetic preganglionic efferent pathways and in sacral parasympathetic afferent pathways in the cat.

Immunohistochemical properties of motoneurons supplying the trapezius muscle in the rat

“…of cervical neuromers of the spinal cord in the cat has been described. The localisation of these neurons corresponds with the localisation of SAN (Vizzard et al 1994a). Moreover, we have observed a moderate number of delicate NOS-positive fibres running very closely to motoneurons, and a small number of NPY-positive fibres found in a very close apposition to CHAT-positive neurons.…”

Cutaneous vasodilatation induced by nitric oxide‐evoked stimulation of afferent nerves in the rat

“…As discussed by Hughes & Brain (1994) it seems most probable that NO is formed either in cells adjacent to afferent nerve fibres or in the nerve fibres themselves. This question cannot be settled on the basis of the available data, but it is worth considering that NO can be formed in mast cells (Salvemini et al, 1991), which could be a non-neural source of NO generated in response to chemical irritants, and in afferent neurones themselves (Morris et al, 1992;Verge et al, 1992;Vizzard et al, 1994). Important in the latter context is the finding that the bradykinin-and capsaicin-induced production of guanosine 3':5'-cyclic monophosphate in cultured primary afferent neurones is blocked by an inhibitor of NO synthase (Bauer et al, 1993), which demonstrates that NO can be formed in stimulated afferent neurones and may play an important role in the chemical activation of sensory neurones and, further on, release of peptide transmitters from them.…”

Increased Expression of Neuronal Nitric Oxide Synthase in Bladder Afferent and Spinal Neurons following Spinal Cord Injury

“…NADPH-d activity is also present in a large percentage of visceral afferent neurons in dorsal root ganglia (DRG) at various levels of the spinal cord of the rat [16,17], In both the rat and cat, NADPH-d is present in a prominent affer ent bundle projecting from Lissauer's tract to the region of the parasympathetic nucleus [6,7,16,18]. This afferent pathway closely resembles the central projections of affer ent neurons innervating the pelvic viscera [19,20], In the cat, the NADPH-d afferent pathways closely resemble vasoactive intestinal polypeptide-containing afferent pro jections to the sacral spinal cord [16,[21][22][23][24], Although NADPH-d was present in primary afferent neurons [11,13,14,17] and in their central projections in rat [6,18] and cat [ 15,16], NOS-IR was not identified [7,15]. These data indicate that in pelvic afferent neurons in normal rats, NADPH-d is not a marker for NOS and that NO is not a transmitter or that immunoreactivity for NOS is not as sensitive as NADPH-d histochemistry.…”

“…In the rat, nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity (a presumed indicator of the pres ence of neuronal nitric oxide synthase (NOS)) [1,2] and neuronal NOS immunoreactivity (NOS-IR) have been identified in sympathetic [3,4] and parasympathetic pre ganglionic neurons [5][6][7] in the spinal cord and in some parasympathetic postganglionic neurons in peripheral ganglia [8][9][10][11][12][13][14], In the cat, NADPH-d activity is present in sympathetic preganglionic neurons; however, it is not present in parasympathetic preganglionic neurons [15]. NADPH-d activity is also present in a large percentage of visceral afferent neurons in dorsal root ganglia (DRG) at various levels of the spinal cord of the rat [16,17], In both the rat and cat, NADPH-d is present in a prominent affer ent bundle projecting from Lissauer's tract to the region of the parasympathetic nucleus [6,7,16,18]. This afferent pathway closely resembles the central projections of affer ent neurons innervating the pelvic viscera [19,20], In the cat, the NADPH-d afferent pathways closely resemble vasoactive intestinal polypeptide-containing afferent pro jections to the sacral spinal cord [16,[21][22][23][24], Although NADPH-d was present in primary afferent neurons [11,13,14,17] and in their central projections in rat [6,18] and cat [ 15,16], NOS-IR was not identified [7,…”