Long-delay associations between drug states produced in rats by injecting two drugs in sequence.

Abstract

Injection of pentobarbital after a rat has consumed saccharin solution usually produces a mild aversion to the saccharin. However, the pentobarbital-produced aversion is eliminated or attenuated by prior pairings of pentobarbital injections with lithium injections. This is called the Avfail (aversion failure) effect. The present experiments dealt with the effect of the temporal relation of the pentobarbital injection to the lithium injection. After forward pairings (pentobarbital before lithium) with delays between the two injections varying among groups from 2.5 min to 320 min, Avfail was invariably obtained. There was little effect of the length of the forward delay, although the Avfail effect appeared to be slightly stronger at 30-40 min or so. When the two drugs were injected simultaneously or in a backward sequence, there was a weakening of the flavor aversion produced by pentobarbital, but this is attributable to habituation to the drugs, not to Avfail.Associative learning occurs when two drug states occur in sequence. It has been demonstrated by injecting rats with a sedative dose of pentobarbital 30 min prior to injection of a toxic dose of lithium. After four to eight such pairings, pentobarbital loses its capacity to produce a saccharin aversion; that is, there is no later saccharin aversion if pentobarbital is injected into the rat just after it has consumed saccharin solution. Control rats that receive equal experience with pentobarbital and/or lithium do not exhibit this effect (Revusky, Taukulis, & Coombes, 1980;Revusky, Taukulis, Parker, & Coombes, 1979). Hence the effect is not due to habituation. The involvement of conditioning is further indicated by findings that a similar effect is obtained with drugs other than pentobarbital and lithium. However, it is not obtained with all combinations of drugs (Cunningham & Linakis, 1980; Revusky, Coombes, & Pohl, in press).Although this effect is due to conditioning,

Avfail in color avoidance learning by starlings (Sturnus vulgaris) and red-winged blackbirds (Agelaius phoeniceus).

“…The results of the present experiments demonstrate that avfail can be obtained in color avoidance learning following pairings of different toxicants (methiocarb and LiCl). As such, the present findings are consistent with those of previous work (e.g., Revusky et al, 1982) and broaden the range of stimuli that can mediate avfail effects from flavor to vision. Moreover, the present experiments produced a new finding, in that avfail was obtained in color avoidance learning with two levels of a single toxicant (methiocarb).…”

“…The first gavage was followed 40 min later by the second. The interval between gavages and the number of toxicant pairings were selected on the basis of work by Revusky and Coombes (1982). The birds in the first group (Lm; n = 4) received LiCl (2 mg/kg) followed by methiocarb (2 mg/kg).…”

“…First, conditioned stimuli in the avfail procedure do not show the usual properties of a conditioned inhibitor (e.g., measurable increases in preference). Second, avfail occurs with intervals up to 320 min between daily preconditioning injections (Revusky & Coombes, 1982; Revusky, Taukulis, & Peddle, 1979). Unlike conditioned inhibition, the conditioned antisickness hypothesis has received some experimental support (Lett, 1983).…”

Conditioned antisickness: Heat as an internal stimulus in conditioning taste aversion and aversion failure in rats.

“…The failure of CS1 to produce an aversion to the taste CS2 in forward-pairing groups is the aversion failure effect. This effect is distinct from the general attenuation of taste aversion produced by stimulus preexposure (e.g., Revusky & Coombes, 1982, Experiment 3).…”

The time course of ethanol tolerance: associative learning

“…For example, Revusky and Coombes (16) examined the associative consequences of the temporal relationship between a pentobarbital injection and a subsequent lithium injection. After forward pairing (pentobarbital before lithium), with delays between the two injections ranging from 2.5 to 320 min among groups, elimination or attenuation of the pentobarbital-produced aversion to saccharin was observed.…”