Distribution of noradrenergic nerve fibers in canine nasal mucosa following selective neurectomies

Noradrenergic innervation of juvenile nasopharyngeal angiofibroma

The glyoxylic catecholaminergic histofluorescence method was employed on tissues from five cases of juvenile nasopharyngeal angiofibroma in order to study the sympathetic innervation present. There was no sympathetic innervation identified in tumor parenchyma while some scant noradrenergic fibers were found in the tumor border. These findings indicate that keeping a dissection surface out of tumor during planned excisions may be very important, as vessels there have more sympathetic innervation which will then result in good vessel contraction in controlling bleeding. Non-diseased nasal mucosa from each patient was used as control tissue, with its submucosa seen to be filled with noradrenergic innervation. Some noradrenergic fibers were also found to innervate the muscle layers of arterioles or venules adjacent to the sphenopalatine foramen.

Trigeminal nasal receptors related to respiration and to various stimuli in cats

In twenty adult cats of either sex under nembutal anaesthesia, we aimed at delineating the sensitive territory of trigeminal nerves innervating the nasal mucosa. The different trigeminal nerves (anterior ethmoidal, posterior nasal and infraorbital nerves) were dissected in the orbit. Activity of these nerves was recorded during spontaneous nasal and tracheal breathing and in response to various stimuli: mechanical (manual probing and air jets) and irritants (ammonia vapours). Multiple and unitary activity recorded in nerve filaments enabled a classification of the receptors on the basis of their discharge pattern as rapidly-, intermediately- or slowly adapting receptors, and as drive or non-drive nasal receptors depending on whether or not the respiratory modulation was preserved during tracheal breathing.

Pre- and post-synaptic alpha-2 adrenoceptors in the canine nasal mucosa

The alpha-2 adrenoceptor radioligand tritiated yohimbine was used to determine the location of pre- versus postsynaptic alpha-2 adrenoceptors in canine nasal mucosa. Using Scatchard analysis, the maximal binding capacity (Bmax) and an apparent equilibrium dissociation constant (Kd) of the alpha-2 adrenoceptor were measured in seven normal dogs and in seven dogs subjected to a unilateral superior cervical ganglionectomy. The results showed that most alpha-2 adrenoceptors in the canine nasal mucosa were located at postsynaptic membranes and very few were located at presynaptic membranes. After superior cervical ganglionectomy, there were no significant changes of the affinity (Kd) and number (Bmax) of the alpha-2 adrenoceptors in the mucosa. These results suggest that the postsynaptic alpha-2 receptors are located extrasynaptically.