Preference-aversion Functions Research Articles

Amiloride does not alter NaCl avoidance in Fischer-344 rats.

Fischer-344 (F-344) rats differ from other common rat strains in that they fail to show any preference for NaCl at any concentration in two-bottle preference tests. Because 100 microM amiloride partially blocks the NaCl-evoked chorda tympani (CT) response in electrophysiological studies, we tested NaCl preference (0.068-0.273 M) in F-344 rats with and without 100 microM amiloride solution as the solvent. A third group was tested with unadulterated NaCl solutions following CT transection. Amiloride had no significant effect on the NaCl preference-aversion function, whereas CT transection significantly reduced NaCl avoidance. These results suggest that the amiloride-sensitive component of the NaCl response is not necessary for F-344 rats to display avoidance of NaCl, but the entire CT input is.

Ibotenic acid lesion of the lateral hypothalamus increases preference and aversion thresholds for saccharin and alters the morphine modulation of taste

In a previous study we showed that bilateral ibotenic acid lesions of the lateral hypothalamus in rats induced an increase in gustatory preference thresholds for saccharin solutions and which were associated with body weight and daily water intake impairments. The first aim of the present study was an attempt to dissociate the body weight and water intake deficits from the increase in gustatory thresholds. For this purpose we compared the effect of simultaneous bilateral lesions of the lateral hypothalamus with the effect of successive lesions in which each unilateral destruction was separated by a 10-day interval. Rats injected with vehicle only (either simultaneously or successively) served as controls. The two types of lesion produced very similar deficits, namely permanent body weight and water intake decreases, as well as a shift to the right in gustatory preference-aversion functions for saccharin (two-bottle procedure). The second aim of the present study was to analyse the effect of morphine (2 mg/kg SC) on saccharin preference in both lesioned and control rats. It was observed that for moderate and high concentrations of the sweetener morphine increased preference for saccharin over water but this effect was similar in both groups of rats. However, with a low concentration of the sweetener (0.3 mM) morphine clearly induced an opposite effect in the two groups of rats: the significant preference for this concentration shown by the control rats after vehicle injection was converted to a neutral response, whereas the neutral response of the lesioned animals after vehicle injection was transformed by morphine to a significant preference for saccharin over water. These results are discussed and in particular suggest that endorphinergic neurons located in the lateral hypothalamus are implicaed in the modulation of palatability.

Opposite effects of SK&F 38393, a dopamine D-1 agonist, and SCH 23390, a dopamine D-1 antagonist, in tests of salt preference/aversion in the rehydrating rat

Male rats were adapted to a 22-hr water-deprivation schedule, and to a 15-min choice test, in which water was available in one drinking tube, and water, 0.064%, 0.16%, 0.4%, 1.0%, or 2.5% NaCl solution, respectively, was available in a second. A typical saline preference-aversion function was obtained. The selective dopamine D-1 agonist, SK&F 38393 (3.0 mg/kg, IP), significantly depressed choice of hypertonic saline solutions (1.0% and 2.5% NaCl solutions), without affecting preference for hypotonic saline solutions. In contrast, the selective dopamine D-1 antagonist, SCH 23390 (0.1 mg/kg, SC), significantly increased the preference measure in the case of hypertonic solutions. These data indicate a role for D-1 receptors in dopaminergic mediation of the descending limb of the saline preference-aversion function.

Effects of postnatal caffeine exposure through dam's milk upon weanling rats.

The effects of postnatal caffeine exposure received through mother's milk were examined in rat pups by administering 0.0125 or 0.05% caffeine solution to the dams throughout lactation. Offspring of caffeine-treated dams showed significantly earlier onset of auditory startle and air righting reflexes. No direct effects of treatment were observed on eight measures of open field activity. At weaning, high-dose caffeine pups exhibited a transient increase in caffeine acceptance in two-bottle taste preference tests and showed cyclic exaggerations in caffeine preference-aversion functions which persisted throughout the 22-day postweaning test period. The caffeine levels in the dams' milk had a 30-fold daily fluctuation reflecting the fluid ingestion pattern related to the light-dark cycle and caffeine elimination rate. Caffeine concentrations in the brains of the pups varied between 0.01 and 9.0 micrograms/g.

Saline intake in hamsters

Experiment 1 assessed the preference-aversion function of hamsters for water and 0.08, 0.15, 0.35, and 0.71 M NaCl solutions in the two-bottle test. Unlike rats, the hamsters did not show a strong preference for isotonic (0.15 M) saline, nor did they exhibit any preference for the other solutions. Experiment 2 examined the effects of hydrochlorothiazide on the hamsters' intake of 0.71 M NaCl solution. The results indicated that this diuretic agent did not cause the hamsters to increase their saline intake relative to the baseline level. Experiment 3 also indicated that a high (5 mg) dose of desoxycorticosterone acetate failed to produce sodium appetite in the hamsters. These results contrast with those found with rats.

Saline intake in gerbils (Meriones unguiculatus)

Experiment 1 assessed the NaCl preference-aversion function of gerbils on the two-bottle test. The results indicated that gerbils do not show the strong preference for 0.9% NaCl that rats do. There was also no significant difference between the gerbils’ intake of 0.9% and 2.0% NaCl. However, there was a significant decrease in the gerbils’ saline consumption when the solution was 4.0% by weight. Experiments 2 and 3 demonstrated that the interposition of a single bottle of hypertonic saline prior to the two-bottle test with isotonic saline and water can decrease the gerbils’ preference for isotonic saline relative to a control group. This effect depended upon the tonicity of the interposed solution. Although rats show a marked reduction in saline preference following exposure to a single bottle of 2.0% NaCl for 24 h, gerbils do not react similarly. However, when the interposed solution is 4.0% NaCl, gerbils show a subsequent reduction in isotonic saline intake. These results suggest parametric differences between the variables affecting fluid regulation of mesophytic and xerophytic adapted animals which reflect species differences in renal handling of osmotic loads.

Use of oral antibiotics in studies of ingestive behavior in rats

The occurrence of chronic respiratory disease (CRD) in animal colonies is a problem encountered in many laboratories. Sixteen female albino rats were used to investigate the effects on food and water intake of the oral antibiotics most often used to treat CRD. Four concentrations (0.01, 0.05, 0.25, and 0.50%) of Tetracycline hydrochloride (TH) and Sodium sulfamethazine (SS) were presented at different times mixed with food or water. The animals were permitted to choose between each drugged and normal food or water combination for 4 days. Both drugs seriously affected fluid intake when placed in solution. When mixed with food, only SS produced a preference-aversion function and increased total daily food and water intake regardless of concentration. The presence of TH in the food had no effect on food choice or on total daily food intake at any concentration.

Septal lesion and experiential influences on saline and saccharin preference-aversion functions

Relatively high (unpalatable) concentrations of saline or saccharin (independent studies) presented in 24 hr choices with water were found to more markedly and persistently suppress the subsequent preference of septal-lesioned rats for lower concentrations when compared with any such shifts in preference displayed by operated-control rats. These data were used to support the notion that the septal region is involved with a comparator mechanism which affects the animal's response to various external and internal cues guiding consumption. In addition, wide individual differences in both groups were presented and discussed to emphasize that future studies should be designed to clarify those uncontrolled genetic and/or early experience variables which must serve, at least in part, to differentially bias the adult animal's consummatory choice behavior.

Effects of ethanol dependence induced artificially in the rhesus monkey on the subsequent preference for ethyl alcohol

Successive preference-aversion functions in an ethanol-water choice situation were obtained for four rhesus monkeys. Each preference sequence consisted of a 9-day period during which the concentration of the ethanol solution offered to the animal was increased systematically from 3–30%. During the second and third ethanol preference sequences, a total of 6 g/kg ethanol was administered daily in two doses to three monkeys with one additional monkey serving as a non-intubated control. Signs of physical dependence on ethanol were exhibited during the second intubation sequence and severe symptoms of withdrawl occurred upon the termination of intragastric ethanol. However, none of the monkeys increased their volitional intake of ethanol over water in terms of the g/kgor proportion measures during the fourth and final 9-day preference sequence. In a second experiment, two monkeys were offered highly palatable ethanol solutions containing orange juice and sucrose for a 13-day period. A subsequent 9-day ethanol preference sequence showed that neither animal increased its proportion or g/kg intake of ethanol significantly nor were signs of withdrawal or physical dependence observed.

Specific hungers in hyperphagic rats

Preference-aversion functions for glucose, sucrose, and sodium chloride were determined using the single-stimulus, brief-exposure procedure. The functions generated by hyperphagic rats were similar to those generated by controls.

Ethanol self-selection in rats: A distinction between absolute and 95 per cent ethanol

Preference-aversion functions for ethanol solutions prepared with absolute or 95 per cent ethanol were determined in normal, untreated rats. In a second experiment these functions were similarly determined except in this case, after 4 days of ad lib water, a second determination was made in which half the animals were intubated with saline and the others with p-chlorophenylalanine ( pCPA), a potent depletor of brain serotonin. In agreement with other studies, the intake of solutions prepared with absolute ethanol was markedly reduced by treatment with pCPA. In marked contrast to this finding, however, was the fact that this compound had little effect on preference-aversion functions for solutions prepared with 95 per cent ethanol. Ethanol intakes during saline intubations were not significantly lower than baseline levels for either group. The observed distinction between absolute and 95 per cent ethanol would seem to be particularly significant since it became apparent only during an experimental treatment and thus could be an important confounding variable in the self-selection study with animals.

Preference-aversion functions for alcohol after cholinergic stimulation of the brain and fluid deprivation

Abstract Rats, in which carbachol reliably produced a polydipsia when micro-injected into the nucleus reuniens, preoptic region, septum or anterior hypothalamus, were simultaneously offered a forced choice of 4, 8 and 12% ethyl alcohol. Although these alcohol solutions were readily accepted by animals deprived of all fluids for 23 hr, these same rats totally rejected even normally preferred alcohol concentrations following a micro-injection of carbachol in any of these chemo-sensitive regions. Thus, it appears that cholinomimetic stimulation of structures in the so-called limbic system “thirst-circuit” does not evoke the same drinking response as that produced by fluid deprivation.

副腎剔出と電気痙攣ショック (ECS) の塩類溶液選好行動に及ぼす効果

It is the purpose of these experiments to demonstrate the variation of the preference-aversion functions for NaCl and for KCl among the normal, the adrenalectomized and the convulsed rats subjected to the self-selection. Each solution was presented in a random order. The obtained data are in terms of the mean intake per 24hrs. of each concentration of solution. The intakes of solutions, tap water and food are expressed on a body weight basis (gm. or c.c./100gm. B.W./day/rat).The results of these experiments are thus as follows:(1) In the self-selection situation, the normal rats showed a typical preference-aversion function for NaCl and for KCl (Fig. 1). The preference threshold is about 0.05 per cent NaCl and about 0.04 per cent KCl solution. The optimal concentration is about 0.9 per cent NaCl and about 0.1 per cent KCl. The aversion threshold is around 1.5 per cent NaCl and 0.9 per cent KCl solution, where all the rats drank less of each solution than the tap water.(2) As can be seen in Fig. 2, the bilateral adrenalectomized rats showed an increase of the intake of NaCl after the rest-period of 16 days. Moreover, when given a chance to choose among water, 0.9 per cent NaCl and 0.1 per cent KCl solution, the adrenalectomized rats showed a greater increase in the intake of NaCl and also a greater decrease in that of KCl than the normal rats.As for the preference-aversion functions, the adrenalectomized rats showed a decrease in the preference threshold (0.02-0.03 per cent) and an increase in the intake of all concentrations of NaCl solution in comparison to the normal rats.(3) The convulsed rats treated daily with ten ECS administrations showed the preference-aversion functions similar to those of the normal ones, differing only in the amount of intakes, i.e., a decrease in NaCl and an increase in KCl for all concentrations employed (Fig. 3).(4) There is a significant difference in the level of the physiological need for Na and K between the normal and the adrenalectomized animals (cf. Table 2 and 3).On the other hand, it is interesting to note that the convulsed rats chose to take significantly less NaCl and more KCl solution in each situation than the normal and the adrenalectomized rats. Therefore, relative Na aversion and K preference by the convulsed animals might result from the functional hypertrophy of the adrenal cortex. This verifies the findings of Rosvold et al., although there is no histological examination of the adrenal gland in this experiment.(5) The convulsed as well as the adrenalectomized animals showed a decrement in body weight immediately after the treatment and a gradual recovery during the remainder of the experiment. The paralysis in the thoracic region downward appeared in the 33.5 per cent of the convulsed group.It may be concluded from these findings that the change of the preference-aversion functions under the conditions of the stress suggests some possible mechanisms by which endocrinological and metabolic responses act together to manifest a behavioral disturbance.