Cholinergic tracing of a central neural circuit underlying the thirst drive.

Cholinergic stimulation of any of a number of interrelated limbic and diencephalic structures in the rat elicits a rapid and marked increase in water intake. We postulate that a generalized Papez circuit mediates the thirst drive, that the circuit is specifically and functionally sensitive to cholinergic action, and that other primary drives depend on closely parallel neural circuits partitioned both structurally and biochemically.