Effects of nasal capsaicin pretreatment and cryosurgery on sneezing reflexes, neurogenic plasma extravasation, sensory and sympathetic neurons.
Local and systemic capsaicin pretreatment as well cryosurgery induced a long-lasting loss of sensory substance P-immunoreactive nerves in the guinea-pig nasal mucosa. In addition, cryosurgery caused a loss of noradrenergic sympathetic nerves, sclerosis of blood vessels, epithelial damage and fibrosis of the mucosa. The sneezing response to local application of capsaicin--but not that to nicotine--was reduced or abolished by capsaicin pretreatment and cryosurgery, while the response to tactile stimulation was unaffected. These effects were long-lasting and still present 2 months after treatment. Local capsaicin pretreatment of the nasal mucosa had no effects on the substance P levels or the Evans Blue extravasation response to i.v. capsaicin in the ureter, indicating that this treatment has no systemic effects on other afferent SP-neurons. It is suggested that local capsaicin pretreatment is a more selective and less traumatic method than cryosurgery to induce a long-lasting desensitization of the nasal mucosa to chemical irritants in hyperreactive disorders of the nose.
Lundblad
L
L
Brodin
E
E
Lundberg
J M
JM
Anggård
A
A
D000818:Animals; D002199:Capillary Permeability; D002211:Capsaicin / Q000494:pharmacology*; D003452:Cryosurgery; D005260:Female; D006168:Guinea Pigs; D008297:Male; D009297:Nasal Mucosa / Q000187:drug effects / Q000294:innervation*; D009475:Neurons, Afferent / Q000502:physiology*; D011292:Premedication; D012018:Reflex / Q000502:physiology*; D012912:Sneezing; D013373:Substance P / Q000032:analysis; D013564:Sympathetic Nervous System / Q000502:physiology*; D013997:Time Factors
D013373:Substance P; D002211:Capsaicin