抄録
Salivary gland function is regulated by the autonomic nervous system, which innervates both salivary acinar and ductal cells. In both the salivary acinar and ductal cells, cholinergic and adrenergic stimulations increase intracellular Ca2+ concentration ([Ca2+]i). However, there is no systematical study comparing sensitivity to the cholinergic and adrenergic drugs between parotid acini and ducts. In the present study, cholinergic and adrenergic drugs-induced changes of [Ca2+]i were investigated in fura-2-loaded rat parotid acini and ducts by using Ca2+-imaging technique. Carbachol (CCh) at 1 μM induced stronger Ca2+ response in parotid acini than ducts whereas noradrenaline (NA) at 1 μM conversely induced lesser response in acini than ducts. CCh-induced Ca2+ responses in both acini and ducts were completely blocked by a M3 receptor selective antagonist (4-diphenylacetoxy-N-methylpiredine methiodide: 100 nM). On the other hand, although NA-induced Ca2+ response in acini was completely blocked by a α1 selective antagaonist (phentolamine: 100 nM), the response in ducts was partially inhibited by the antagonist. The phentolamine-resistanse response in ducts was completely blocked by a β selective antagonist (propranolol: 1 μM) and a β selective agonist (isoproterenol: 10-100 μM) induced increment of [Ca2+]i in ducts, but not acini. These results suggest that there are different sensitivitiies to cholinergic and adrenergic agonists between parotid acini and ducts. [J Physiol Sci. 2008;58 Suppl:S154]
