Conditioned drinking produced by procaine, NaCl, and angiotensin

Demonstrated conditioned drinking in 64 male and 32 female sprague-dawley albino rats using 3 techniques. Increasing concentrations of subcutaneous nacl injections increased unconditioned drinking (ucr) systematically but did not increase conditioned drinking (cr). Increasing concentrations of procaine-hcl injections systematically increased both unconditioned and conditioned drinking, and demonstrated dissociation of ucr and cr in classical conditioning. Conditioned drinking was also produced by procaine and nacl procaine delivered through a chronically implanted perforated tube under the back and by injections of angiotensin to the hypothalamus. Unlike procaine-conditioned drinking which did not extinguish, angiotensin-conditioned drinking extinguished rapidly. It is suggested that procaine may act like a poison and the conditioned drinking it produces may serve to avoid illness, while conditioning produced by angiotensin may be more like the conditioning of natural thirst. (23 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved).