Receptors for catechol amines in the submaxillary glands of rats.

The conception of aand P-receptors for catechol amines was originally based on experiments with heart and smooth muscle (Ahlquist, 1948). The present investigation deals with such receptors in glandular tissue. The starting-point was the observation that guanethidine causes a flow of saliva from the submaxillary gland which is completely abolished by dihydroergotamine in cats but only reduced by this drug in rats; further experiments disclosed that this applies to secretion evoked by noradrenaline also (Emmelin & Str6mblad, 1963). It may therefore be assumed that the rat salivary gland is supplied not only with a-, but also with P-receptors. This conclusion is supported by the fact that saliva flows from the mouth of rats after intraperitoneal injection of isoprenaline (Selye, Veilleux & Cantin, 1961; Argonz, 1962; Wells, 1962; Pohto & Paasonen, 1964); a salivary flow has also been observed from the submaxillary duct of rats after large doses of isoprenaline given intraperitoneally (Schneyer, 1962; Ohlin, unpublished) or small intravenous doses (Ohlin, 1964).