Neuronal nitric oxide synthase-immunoreactivity: A neuromodulating system independent of peripheral nasal gland denervation in guinea pig nasal mucosal tissue after treatment with botulinum toxin type A

The influence of botulinum toxin type A (BTA) on cellular mechanisms has not been studied in much detail. Since nitric oxide (NO) is of increasing interest as a neuromodulator in the innervation of the nose, its localization was examined in the nasal mucosa of guinea pigs treated with BTA or saline. Neuronal nitric oxide synthase-immunoreactivity (nNOS-IR) was found around vessels and nasal glands. Immunoreactivity was seen in the respiratory epithelium, in the periost and the osteocytes of the turbinate bone. A distinct interindividual difference in the strength of nNOS-IR was obvious among the animals, but there was no difference in the strength of immunoreactivity between the animals treated with BTA or saline. NO might therefore contribute to the regulation of vascular tone, glandular function, respiratory epithelial cell function and bone metabolism. BTA does not seem to influence the processes regulated and modulated by NO. This may represent a benefit for the application of BTA.