Plasma extravasation through neuronal stimulation in human nasal mucosa in the setting of allergic rhinitis

Sanico, Alvin M., Satsuki Atsuta, David Proud, and AlkisTogias. Plasma extravasation through neuronal stimulation in humannasal mucosa in the setting of allergic rhinitis. J. Appl. Physiol. 84(2): 537-543, 1998.We havepreviously shown that capsaicin nasal challenge in subjects withallergic rhinitis produces a dose-dependent increase in the albumincontent of nasal lavage fluids. In the present set of studies, wedetermined whether this observation represents plasma extravasationthat is neuronally mediated. To evaluate whether glandular secretionscontribute to the albumin increase in nasal lavage fluids, volunteerswith allergic rhinitis were pretreated with atropine or placebo before capsaicin challenge. Atropine significantly reduced the volume ofreturned lavage fluids and their lysozyme content but increased theiralbumin and fibrinogen content. To assess the contribution of sensorynerve stimulation, subjects with allergic rhinitis were pretreated in asecond study with lidocaine or placebo before capsaicin challenge.Lidocaine significantly attenuated the capsaicin-induced increases inthe volume of nasal lavage fluids, as well as their lysozyme andalbumin content. To rule out the possibility of a direct effect oflidocaine on blood vessels rather than on nerves, healthy subjects werepretreated in a third study with lidocaine or placebo before bradykininnasal challenge. Lidocaine did not affect the bradykinin-inducedincrease in the albumin content of nasal fluids. We conclude that, inallergic rhinitis, high-dose capsaicin induces plasma extravasation inthe human nose and that this effect is neuronally mediated. Thisprovides more definitive evidence that neurogenic inflammation canoccur in vivo in the human upper airway.

     

Hyperosmolar saline induces reflex nasal secretions, evincing neural hyperresponsiveness in allergic rhinitis.

We investigated whether hyperosmolar saline (HS), applied via paper disk onto the septum of one nostril, induces a nasal secretory response. Furthermore, we examined whether this response is accentuated in patients with active allergic rhinitis (AR) compared with healthy volunteers. Unilateral HS produced significant nasal secretions both ipsilateral and contralateral to the site of challenge in the AR group and only ipsilaterally in the healthy group. The HS-induced nasal secretions were significantly greater in the AR vs. the healthy subjects. In a separate study, we ascertained that the nasal response to HS is neurally mediated and found that ipsilateral nerve blockade with lidocaine significantly attenuates the HS-induced secretions bilaterally. In another group of AR subjects, we determined whether nociceptive fibers were involved in this response and found that sensory nerve desensitization with repeated application of capsaicin attenuated the HS-induced nasal secretions. Finally, we determined whether the secretory hyperresponsiveness in AR is attributable to increased reactivity of submucosal glands rather than of nerves. We found that the dose response to methacholine, which directly stimulates the glands, was identical among AR and healthy subjects. We conclude that, in AR, nasal challenge with HS induces significantly greater reflex secretions involving capsaicin-sensitive nerve fibers, consistent with the notion of neural hyperresponsiveness in this disease.     

Grain filling pattern and cytokinin content in the grains and roots of rice plants

Grain filling patterns and their relationships withzeatin (Z), zeatin riboside (ZR), indole-3-acetic acid(IAA) and gibberellin (GA) contents in the grains androots during grain development were examined in sixrice (Oryza sativa L.) genotypes grown in thefield and in water culture. Three grain fillingpatterns based on the filling rate of superior andinferior spikelets were observed, i.e., fastsynchronous: all spikelets started filling early andfast at the early filling stage; slowsynchronous: all spikelets filled slowly at the earlyfilling stage and reached the maximum filling ratelate; and asynchronous: superior spikeletsstarted filling and reached the maximum filling ratemuch earlier than the inferior ones. The order ofgrain filling percentage in the three types of grainfilling patterns was: fast synchronous >asynchronous > slow synchronous. Changes in Z + ZRcontents in the superior and inferior spikelets wereassociated with the grain filling patterns. Grainfilling percentage was significantly correlated withZ + ZR contents in the grains and roots at the earlyand middle grain filling stages. IAA and GA(GA¹ + GA³ + GA⁴)contents in the grains and roots were notsignificantly correlated with grain fillingpercentage. The results suggest that cytokinins in thegrains and roots during the early phase of graindevelopment play an important role in regulating grainfilling pattern and consequently influence grainfilling percentage.