The role of substance P-containing fibers in sympathetic ganglia: effect of capsaicin

Effect of NGF antibodies on mast cell distribution, histamine and substance P levels in the knee joint of TNF-arthritic transgenic mice

We have previously shown an increase in nerve growth factor (NGF) levels and in mast cell (MC) distribution in the synovium of patients affected by rheumatoid arthritis. We now report that purified NGF antibodies injected into arthritic transgenic mice carrying the human tumour necrosis factor-alpha (TNF-alpha) gene caused reduction in the number of MCs, as well as a decrease in histamine and substance P levels within the synovium. These observations suggest that NGF antibody might be useful in studying the role of these pro-inflammatory markers in joint arthritis.

Treatment of reflex sympathetic dystrophy with topical capsaicin. Case report

A 31-year-old woman with intractable reflex sympathetic dystrophy experienced nearly complete, though temporary, resolution of pain following 3 weeks of topical capsaicin. We propose that capsaicin may be a useful treatment for reflex sympathetic dystrophy, either by depleting substance P from primary afferent neurons that mediate allodynia, or by modulating sympathetic efferent activity.

Micturition in the unanesthetized rat: effects of intrathecal capsaicin, N-vanillylnonanamide, 6-hydroxydopamine and 5,6-dihydroxytryptamine

Unanesthetized rats chronically implanted with vesical and intrathecal catheters were injected intrathecally (i.t.) with either capsaicin (CAP), N-vanillylnonanamide (VN), 6-hydroxydopamine (6-OHDA), or 5,6-dihydroxytryptamine (5,6-DHT). The volume-evoked micturition reflex was assessed by cystometrography before, and 2 h, 1 day and 7 days after injection. In control and vehicle-injected rats, the infusion of saline into the bladder resulted in a periodic contraction of the bladder with synergic sphincter relaxation. One day after i.t. CAP and VN (70 micrograms each), 50% and 30% of the animals displayed a blockade of the micturition reflex, respectively. In these animals, the infusion of saline resulted in a gradual rise in bladder pressure up to a plateau (overflow pressure) equivalent to the predrug bladder opening pressure. When the plateau was reached, continuous dribbling of urine with no bladder contractions was observed. Most of the affected rats displayed some micturition responses by day 7. Following i.t. injection of 5,6-DHT (20 micrograms) or 6-OHDA (20 micrograms), the micturition reflex displayed small but significant increases in bladder volume with no changes in pressure profile. Small primary afferents, sensitive to the neurotoxic effects of CAP and VN appear to play a major tonic role in the regulation of the micturition reflex in unanesthetized rats. Serotonergic and adrenergic descending pathways might play a role in the maintenance of resting bladder tone.

Distribution of substance P neurons in the epithalamus of the rat: an immunohistochemical investigation

Substance P (SP) immunoreactivity was studied in the epithalamus of intact and superior cervical ganglionectomized female rats by using the peroxidase-antiperoxidase immunocytochemical technique. Cells containing immunoreactive SP were located in the medial habenula, and SP fibers were observed in the lateral habenula, habenular commissure, pineal stalk, and the pineal organ. Bilateral removal of the superior cervical ganglia did not affect the immunocytochemical staining of SP-containing cells and fibers 15-30 days later. It is suggested that habenular neurons containing SP send projections into the pineal organ of the rat.