Comparison of paradoxical salivatory responses to chlorosyle and atropine in a denervated human parotid gland.

In the case of the denervated human parotid gland, atropine is a cholinopositive agent that causes an extremely intense and prolonged (up to 3-5 h) salivation. An attempt was made to find out the extent to which the "weight increase" principle had an effect on such a gland, i.e. whether larger analogues of atropine which has a relative molecular mass of 289.4 would stimulate or inhibit the paradoxical salivation. The studies involving chlorosyle of a mass of 355.89 were carried out in seven subjects during the last three years. The cholinopositive activity of chlorosyle, as a ligand with increased weight on both poles, on a denervated gland, was several times lower than that of atropine. With the increase of the ligand's dosage, the cholinoexciting activity of chlorosyle decreased sharply and was just restricted by the initial cholinomimetic excitement transforming into a blockade, which may be compared with the action of depolarizing myorelaxants. The data obtained may provide a foundation for conceptualization of the expansion of a response-active cholinopositive zone in a cholinoreceptor deprived of nervous control, which, probably, results from relocation of hydrophobic segments to the macromolecular periphery or, more precisely, to the synthesis of receptors with another part of the zone. The chlorosyle radicals with increased length and weight, while contacting the hydrophobic segments, conditioned the occurrence of cholinoblocking activity and inhibition of the cholinoexciting effect.(ABSTRACT TRUNCATED AT 250 WORDS)