The effect of adrenocorticotrophic hormone (ACTH) on avoidance conditioning in the rat.

Abstract

The various changes in mood and behavior that may occur in patients treated with adrenocorticotrophic hormone (1,6) have made it pertinent to assess the effect of exogenous ACTH on behavior motivated by noxious stimulation. That some effect of ACTH on avoidance conditioning does occur is revealed in studies discussed by Mirsky, Miller, and Stein (5).In avoidance conditioning the animal must respond appropriately to the conditioned stimulus in order to prevent the occurrence of the painful unconditioned stimulus. Consequently, it may be postulated that any modification of the response to a noxious stimulus would be reflected in avoidance conditioning. METHOD SubjectsThirty-one male Wistar rats 100 to 120 days old were used. The Ss were maintained on an ad libitum supply of food and water throughout the experiment. The animals were randomly assigned to the experimental conditions. A pparatusThe tests were conducted in a two-compartment apparatus. The unit was 23 in. long, 7 in. wide, and 9 in. high. A 2-in. barrier of stainless steel liars % in. in diameter, l^ in. apart, separated the two compartments. The top bar of the barrier was mounted on bearings to prevent perching. The floor was a grid of stainless steel rods identical in size and spacing to those described for the barrier. The two ends and the top were made of wood, and painted while inside. One side consisted of a sheet of white milk glass. Illumination was provided by two 25-w. bulbs located behind this translucent glass. The remaining side consisted of two pieces of plain glass with a black cloth inserted between them. This made it possible to observe the animal without the distraction of movements by E.A push-button switch activated a buzzer and a timedelay relay that automatically delivered a shock to the animal after S sec. if it failed to respond (110 v. with 85,000 ohms in series with the animal). Another push-

Neural and endocrine effects on classical conditioning: A comparison of ACTH and hippocampectomy

“…The increased resistance to extinction of avoidance responding found in hippocampal animals (Isaacson et al, 1961) has also been demonstrated in ACTH-injected animals (Murphy & Miller, 1955). The deficit in spontaneous alternation that has been observed in hippocampally lesioned animals (Roberts, Dember, & Brodwick, 1962) has been replicated via elevation of ACTH as well (File, 1978).…”

Effects of ACTH and zinc phosphate vehicle on shuttlebox CAR

“…Murphy and Miller (1955) reported that exogenous ACTH served to prolong the conditioned avoidance responding (CAR) of rats in the two-way shuttlebox during extinction. Later, essentially the same finding was reported with adrenalectomized rats (Miller & Ogawa, 1962).…”

“…Animals studied include the rat (Murphy & Miller, 1955), cat (Endroczi & Lissak, 1962), mouse (Koranyi et al, 1967), rabbit (Bertolini et al, 1969), dog (Ferreri et al, 1963), monkey (Mirsky et ai, 1953), and man (Cleghorn, 1952). Some of the behaviors include: sexual behavior (Bertolini et aI, 1969), the "stretching syndrome" (Ferrari et al, 1963), active avoidance (Murphy & Miller, 1955), passive avoidance (Weiss et al, 1969), and CER (Levine & Jones, 1965).…”

“…Apparatus The Ss were tested in two-way shuttleboxes similar in design to those used by Murphy & Miller (1955) and Bohus & De Wied (1966); they were 18 x 6 x 10 in.…”

Phenothiazine Derivative on Avoidance Behavior in Rats

“…Since Sheffield and Temmer (1950) have suggested that an avoidance response persists for an unusually long time in comparison with other type of conditioning (escape response), Murphy and Miller (1955) developed the method to establish a high degree avoidance response which was resistant to extinction. Many authors, Fellows and Cook (1957), Cook and Weidley (1957), Miller et al (1957), Irwin et al (1959Irwin et al ( , 1961, , and others observed the suppression of conditioned avoidance behavior by use of phenothiazine tranquilizers effective in the treatment of psychoses.…”