Parasympathetic control of blood circulation and secretion in the nasal mucosa

The effects of selective parasympathetic nerve activation on the secretory response and the vascular exchange and capacitance sections in the cat nasal mucosa were studied. The vascular events were investigated by measuring the local disappearnce of 125I- and changes in gross pulse rate from 131I- labelled serum albumin as monitored over the nose. A frequency-dependent increase in nasal secretion and local blood content occurred in the range 0.5-12 imp/sec: an increase in disappearance rate was observed at the same time. This indicates that the vascular and secretory responses are activated simultaneously. The secretory responses, but not the vascular events, were shown to be blocked by atropine. The results thus shown that the postganglionic parasympathetic mediator of nasal secretion is cholinergic, whereas the vasodilatation appears to be due to a different mechanism, which is not sensitieve to atropine. The beneficial effect of some antihistamines in vasomotor rhinitis may thus be due to their anticholinergic properties.