Capsaicin and nicotine‐sensitive afferent neurones and nasal secretion in healthy human volunteers and in patients with vasomotor rhinitis

Abstract

1 Applications of capsaicin, nicotine and methacholine were made locally onto the nasal mucosa in human controls and patients suffering from hyperreactive nasal disorders. Perception of sensation was registered as a sympton score and secretion quantified. The sensory reaction (irritationpain) to capsaicin was similar in the three groups studied, i.e. controls, a group of patients with the diagnosis of vasomotor rhinitis and a group of patients with increased nasal secretion as the main symptom of the hyperreactive disorder. Nicotine induced only a mild itching sensation in the three groups. However, capsaicin and nicotine challenge caused a significantly larger secretory response in the last group than in the unselected vasomotor rhinitis group and in the control group. 2 Pretreatment with muscarinic receptor antagonists almost completely abolished the secretory response to both capsaicin and nicotine, and blocked methacholine-induced secretion. Furthermore, pretreatment with a combination of local anaesthetic and vasoconstrictor agent abolished the capsaicin-induced irritation, as well as the capsaicin-and nicotine-induced secretion on both the ipsilateral and the contralateral side. Therefore, no clearcut contribution seems to be exerted by locally released peptides from sensory neurones as direct trigger substances for the secretory response to capsaicin. 3 In conclusion, the nasal secretory response, in man, to both capsaicin and nicotine, seems to be mediated via cholinergic parasympathetic reflexes. In patients with hyperreactive non-allergic disorders of the nasal mucosa with rhinorrhea as the main complaint, the enhanced secretion may be due to a hyperreactive efferent cholinergic mechanism rather than hypersensitive irritant receptors on capsaicin-and nicotine-sensitive sensory neurones. Challenge with irritant agents seems a useful test for the evaluation of both afferent and efferent reflexogenic responses in hyperreactive disorders of the nasal mucosa.

Agonistic sensory effects of airborne chemicals in mixtures: Odor, nasal pungency, and eye irritation

“…So far, the evidence suggests that capsaicin acts on certain C fibers, particularly polymodal nociceptors, and some A[j fibers (Buck & Burks, 1986). Topical application of capsaicin in the human nasal mucosa produces sneezing, secretion, and a burning and painful sensation that can be prevented with a local anesthetic (Geppetti et aI., 1988;Stjarne, Lundblad, Lundberg, & Anggard, 1989). Repetitive local application in the human nasal mucosa also produces desensitization (Sicuteri et aI., 1989).…”

Pathophysiological Features of the Nasal Mucosa in Patients with Idiopathic Rhinitis Compared to Allergic Rhinitis

“…Further studies are necessary to determine the mechanisms by which sensory hyperreactivity [3, 27]is initiated in idiopathic rhinitis.…”

Sympathetic and parasympathetic interaction in vascular control of the nasal mucosa in anaesthetized cats.

“…Parasympathetically mediated nasal vasodilatation occurs in several pathological situations such as allergic rhinitis (Konno & Togawa, 1979) and nonallergic nasal hyper-reactivity involving the sensoryparasympathetic reflex arc (Stjiirne, Lundblad, Lundberg & Anggard, 1989). Consequent to the present observations, the role of exogenous NPY as a modulator of parasympathetically evoked nasal vasodilatation should be studied in patients with mucosal diseases associated with vasodilatation, increased vascular permeability and plasma exudation.…”