The role of the tractus diagonalis in drinking behaviour induced by central chemical stimulation, water deprivation and salt injection

Abstract

The role of the tractus diagonalis in drinking behaviour induced by central chemical stimulation, 23-hr water deprivation and injection of a hypertonic sodium chloride solution was investigated by means of central and peripheral administration of atropine and methylatropine. The effect of the same doses of centrally and peripherally administered anticholinergics was greater on carbachol-induced drinking than on deprivation-induced drinking. Salt-induced drinking was only influenced by peripheral administration of the anticholinergics.

The results indicate the presence of a central cholinergic and a peripheral cholinergic active mechanism in carbachol-induced drinking; a central cholinergic, a peripheral cholinergie and a non-cholinergic mechanism in deprivation-induced drinking; and a central cholinergic, a peripheral cholinergic and a non-cholinergic mechanism in salt-induced drinking. It is concluded that a cholinergic system cannot be the system that has an overall control over water intake behaviour. The results obtained make it questionable whether the tractus diagonalis has a specific function in the series of events that lead to water intake after water deprivation or a salt injection.