Infant Guinea Pigs Research Articles

Ontogenesis of circadian sleep-wakefulness rhythms and developmental changes of sleep in the altricial rat and in the precocial guinea pig.

Ontogenesis of circadian sleep-wakefulness rhythms and other developmental changes of sleep were examined in the altricial rat and in the precocial guinea pig. Circadian sleep-wakefulness rhythms began to emerge on the 4th-4.5th week after birth in rats born and raised not only under light-dark (LD) 12:12 h lighting schedule but also under a constant light condition. Only ultradian rhythms were recognized in the rat up to 2.5-3.5 weeks after birth. Unlike the rat, the guinea pig did not develop significant diurnal and circadian sleep rhythms during the course of its growth. Sleep-wakefulness rhythms of the 1-week-old infant guinea pig were very similar to those of the adult. During the development of the altricial rat the periods of slow wave sleep (SWS) and paradoxical sleep (PS) cycles, and the amounts of SWS per day increased. On the other hand, the amounts of PS per day and the length of the PS episodes decreased. For the guinea pig, however, these parameters of sleep were apparently constant throughout development.

Effects of noise on infant and adult guinea pigs

Six infant guinea pigs were subdivided into a control group (no noise exposure) and infant exposed group (exposed at 2 days) and an adult exposed group (exposed at 2 months). 4 kHz narrow band exposure doses of 1 h at 115 dB SPL were presented to the two experimental groups. A conditioned suppression technique used to measure thresholds revealed a significantly greater loss for the infant exposed subjects than either the control or adult exposed subjects. The current project added hair cell counts to the behavioral data using surface preparation techniques. All hair cell counts were taken after greater than two months post trauma. Although the number of subjects may be small, consistent trends in the data suggest a significantly greater susceptibility of the infant ear over that of the adult ear. These trends would suggest concern about the definitions of hazardous noise level doses for this population.

Altered function and histology in guinea pigs after inhalation of diesel exhaust

Health effects of inhaled diesel engine exhaust were evaluated in infant guinea pigs following 4 and 8 weeks of exposure. Animals were exposed to 1 part exhaust diluted by 13 parts clean air for 20 hr/day, 7 days/week. Lung function, electrocardiogram, growth rate, and histopathology were assessed following exposure. After 4 weeks, animals exposed to irradiated exhaust, showed a 35% increase in pulmonary air flow resistance, and a small but significant decrease in heart rate. Necropsy, after 8 weeks, showed exhaust exposed animals to have black discoloration of the lungs and increased lung to body weight ratios. Microscopic examination of the lungs from these animals revealed black particulate material in the cytoplasm of alveolar macrophages and in draining lymph nodes.

Glutamic acid and sodium levels in the nucleus arcuatus of the hypothalamus of adult and infant guinea pigs after oral monosodium glutamate

Monosodium glutamate (MSG) administered orally at 4 g/kg body weight (b.wt.) as a 20% solution (w/v) to 55–60-day-old guinea pigs and at 2 g/kg b.wt. as a 20% solution (w/v) to 3-day-old guinea pigs did not increase glutamie acid (GA) or sodium levels in the nucleus arcuatus of the hypothalamus (NAH) or in the thalamus lateralis (TL). Sodium chloride given by gavage at doses of sodium equimolar to MSG resulted in an increase of sodium content only in the NAH of infant guinea pigs.

Effects of imipramine on infant guinea pig distress vocalization.

Effects of imipramine on infant guinea pig distress vocalization.

Social attachment of the infant guinea pig to its parents in a two-choice situation

Twenty-four domestic guinea pigs (12 of each gender) served as subjects in this study, which investigated attachment by testing amount of time (maximum 5 min) the infants spent close to either the mother or the father in a two-choice situation during Weeks 2, 4, 6, and 8 after birth. Significantly more time was spent close to the mother during Weeks 2 and 4; reaction to the father appeared random. Time spent close to the mother declined across weeks, suggesting that maternal attachment weakens as the infant matures.

Attachment and separation distress in the infant guinea pig.

This study systematically examined separation-induced distress vocalization in the infant guinea pig. Experiment I found that under maximum separation from both social and physical surroundings, the distress vocalization rate remained high for the 1st 4 weeks and then continuously declined to near zero by Week 12. Repeated testings had no effect on habituation of the rate during Week 5. Experiment II, using separation distress vocalization responses to the social (the mother) and the physical (the home pen) environments, showed that when the mother was present the vocalization rate was extremely low, and when she was absent the rate was moderate if the subject was isolated in the home box and high if the subject was in an unfamiliar box. Experiment III confirmed the finding that primary social attachment took place toward the mother. These results corroborate other attachment measures, and indicate the usefulness of the vocalization technique for the study of attachment in the infant guinea pig.

Reaction of parents to recorded infant guinea pig distress vocalization

The study investigated the possible role that separation distress vocalization of the infant guinea pig (Cavia porcellus) plays in parental attention. Both parents of eight litters were tested biweekly for 8 weeks after the birth of the litters. The importance of infant distress vocalization to the parent was assessed through comparison of each parent's reaction to being placed in an unfamiliar environment which was either (a) neutral, (b) containing a recording of infant distress vocalization, or (c) containing a recording of white noise. Results showed that the mothers only strongly responded to a recording of infant distress vocalization during the first week after birth, and that the fathers did not respond at any time.

Development of directional responses toward sound by young guinea pigs

Infant guinea pigs were tested in a circular apparatus for their tendencey to approach the source of auditory stimulation. A tape recording of guinea pig vocalizations was played over a loud speaker and the incidence of directional responses was noted. Even without external reinforcement there was a tendency to approach the particular stimulus used in this study within the first four days after birth. In order to determine the cues involved in infant localization, animals were tested with wax plugs inserted in one ear or in both ears. The plugs attenuated but did not totally eliminate sound entering the ear. Directional responding was reduced to chance by monaural blocking, but not by binaural blocking. Similar results were obtained with older animals eleven to thirty-one days of age. Furthermore, directional responding was impaired in animals raised from birth with monaural ear plugs, but tested without ear plugs. These results indicate that sound localization occurs early in development in the guinea pig, that binaural cues are important, and that monaural deprivation can affect subsequent responding.

OPERANT CONDITIONING IN NONDEPRIVED ADULT AND INFANT GUINEA PIGS

OPERANT CONDITIONING IN NONDEPRIVED ADULT AND INFANT GUINEA PIGS

Guinea-pig vocalizations: their structure, causation and function.

A colony of approximately 150 adult and infant guinea-pigs was studied in order to investigate the structure, causation and function of guinea-pig vocalizations. Behaviour and sound recording were made in a wide variety of contexts and sounds were analysed on the Kay Electric Sonagraph 6061 B. Sonagrams were measured, and on the basis of physical structure alone, 11 call types were distinguished. Behavioural records were examined and it was suggested that 5 functional categories existed. The significance of vocal communication in guinea-pig social behaviour was discussed.

A Developmental Study of Interactions Between Young and Adult Guinea Pigs (Cavia Porcellus)

AbstractTwo studies examining the interactions between adults and young guinea pigs were reported. Both studies were of the same design, and consisted of a series of time-sampling observations of the social behaviour of a litter of young guinea pigs and their mother, housed in a single cage with either an adult virgin female (in the first experimental condition) or an adult male (in the second experimental condition). Daily observations were also made, after the infant animals had been removed from their cage for a few hours each day, on reintroducing them to the two adult guinea pigs. It was found that although infant animals interacted with the non-lactating adult, in particular the adult male, these social interactions tended to be unlike those between the young and their mother. Responses such as suckling and all other physical contact were directed predominantly to the mother, whereas near responses (remaining near an adult but not in contact with it) occurred more often in relation to the other adult. It was found that infants could distinguish the adults by distal cues, and in the reintroduction study the mother was preferred to the other cohabitant adult on all behavioural measures. It was suggested that infant animals may recognise classes of adults (for example, male, lactating female, non-lactating female) at a distance, but individuals may only be distinguished by proximal cues, since an earlier study has found that infants did not distinguish their mother from another lactating female at a distance. In general, no sex differences in behaviour were found in the infant animals. It was concluded that the infant guinea pig plays a somewhat larger part in enforcing mother-young interactions than was previously thought, and it was suggested that observations on a colony of guinea pigs would be of great value in further investigating this whole area of research.

Taste-aversion learning in infant guinea pigs.

Infant guinea pigs were hand-fed a 10% sucrose solution and poisoned after delays of 0 min, 30 min, or 24+ hr. Subjects in the first 2 groups showed significant sucrose aversions when tested more than a month later. No significant difference existed between the 0- and 30-min groups; no deficiency in this type of learning was evident even in neonates. All 3 groups showed a lower sucrose preference if first exposed at ages 0-6 days than at 7-11 days. Evidently exposure to sucrose at the earlier ages was less effective in reducing later neophobia to sucrose; although the youngest animals had no evident deficiency in learning aversions, they may have been deficient in learning "safety".

On the Nature of Mother-Infant Interactions in the Guinea-Pig (Cavia Porcellus)

Abstract Two studies concerning the specificity of social interactions between mother and infant guinea-pigs were reported. The first study consisted of a series of time-sampling observations of the social behaviour of 2 litters of young guinea-pigs and their mothers housed in a single cage. In a second series of observations, 2 cohabitant litters were separated from their mothers for a few hours each day and their social interactions noted when they were subsequently individually reintroduced to the 2 lactating females. Although the infants suckled significantly more often from their biological mother in each study, and were more often observed to be near or in contact with their mother as opposed to the other female, there were frequent social interactions between infants and the other female (including suckling). When reintroduced to the 2 adult females, the offspring were indiscriminate in their initial approaches towards the latter and likewise showed no preference for mother vs other female in their following responses. The adult females approached their own offspring more often than the other infants when they were initially placed into the cage. No significant differences were found between subsequent approaches towards, or avoidance of, own vs other offspring, however. It was concluded that a reciprocal loose bond of attachment exists between infant and mother guinea-pig - with the mother being able to recognize her offspring at a distance, while the infant apparently requires proximal cues for identification of its mother. An attempt was made to relate the nature of this bond to the highly precocial state in which guinea-pigs are born and their relative independence of maternal care-taking.

Exploration and attachment behaviour in infant guinea pigs.

Abstract Individual infant guinea pigs were tested oncde a week during the first 4 weeks of life in a square enclosure which was separated from a smaller enclosure (confinement cage) by a wire-mesh partition. In the Experimental condition (E) the mother and siblings of the subject were present in the confinement cage during testing - while in the Control condition (C) the confinement cage was empty during testing. The young guinea pigs tested in the presence of the mother and siblings displayed a much greater level of activity (i.e. exploratory behaviour) than did those tested with the empty confinement cage. They thus appeared to use the mother and/or siblings as a base from which to explore a novel environment. Exploratory behaviour in condition E showed a significant increase between weeks I and 2 (possibly due to the waning of an initial immobility reaction), and a gradual decline over weeks 3 and 4 (believed to be due to habituation to the test enclosure). In condition C, there were no significant differences in activity between trials. The guinea pigs tested in the presence of the mother and siblings spent significantly more time near the wire partition separating the test enclosure from the confinement cage than did the control subjects - for whom the confinement cage was empty. Subjects in condition E spent significantly more time in the proximity of the mother and siblings during weeks 2-4 as compared to week I. The responsiveness of the young guinea pigs to conspecifics therefore appears to have increased over the first 2 weeks post-partum. The possible adaptive significance of the interaction between exploration and attachment behaviour was discussed.

Distinct patterns of entry of two non-metabolizable amino acids into brain and other organs of infant guinea pigs.

Abstract— Entry of [3‐14C] α‐aminoisobutyric acid (AIB) and [1‐14C] 1‐aminocyclopentanecarboxylic acid (cycloleucine) into the brain and other organs of the infant guinea pig has been investigated in vivo. The entry of [14C]AIB into brain was markedly restricted in comparison to its entry into other organs. The mean distribution ratio (14C in tissue water/14C in plasma water) achieved in brain at 45 min after administration of a pulse of [14C]AIB was 0.3. All other organs studied concentrated [14C]AIB from the blood stream, with the greatest uptake occurring in liver and kidney, in which distribution ratios reached values of 5–10. In contrast to AIB, [14C]cycloleucine entered the brain at a rate approximately the same as that into other organs. Distribution ratios for [14C]cycloleucine ranged between 0.5 and 2.0 for all organs. During the first few days of postnatal life, there was a sharp increase of concentrative uptake of [14C]AIB into liver and kidney. The entry of [14C]AIB into brain remained unchanged during this period. There was a small (35 percent) decrease in the rate of entry of [14C]cycloleucine into brain during the first 3 days of postnatal life. Since [14C]AIB is known to be concentrated from the surrounding medium by brain slices in vitro, we concluded that the locus of restriction of the entry of [14C]AIB into the brain in vivo is at the blood‐brain barrier. We hypothesize that this property of the barrier is important in preventing concentrative uptake of pharmacologically active and potentially harmful amino acids by brain tissue.

Effects of tetrodotoxin and anaesthetics on brain metabolism and transport during anoxia.

1. Tetrodotoxin, at concentrations at which it abolishes generation of action potentials in the nervous system, enhances by about 300% the rate of anaerobic glycolysis of brain-cortex slices from adult rats, or from adult and infant guinea pigs. This occurs to a greater extent in Ca(2+)-deficient incubation media than in Ca(2+)-rich media. Tetrodotoxin has no accelerative effect on cerebral aerobic glycolysis. 2. Tetrodotoxin does not affect the rate of anaerobic glycolysis of 2-day-old rat brain-cortex slices, nor that of adult rat kidney medulla, nor that of an extract of an acetone-dried powder of brain. 3. Tetrodotoxin does not affect the rate of penetration of glucose into brain slices. 4. Its effect is not apparent if it is added 10min or later after the onset of anoxia. 5. Its effect diminishes as the concentration of K(+) in the incubation medium is increased while that of Na(+) is decreased. 6. Its salient effect, at the onset of anoxia, is to diminish influx of Na(+) into, and efflux of K(+) from, the brain slices. 7. Substances that promote cerebral influx of Na(+), e.g. protoveratrine, sodium l-glutamate, diminish the accelerative action of tetrodotoxin. 8. It is concluded that tetrodotoxin exerts its effect on anaerobic glycolysis by suppressing, at the onset of anoxia, the generation of action potentials and thereby the accompanying influx of Na(+) and efflux of K(+). It is suggested that glycolytic stimulation occurs because a rate-limiting step, e.g. operation of pyruvate kinase, is stimulated by K(+) and depressed by Na(+). 9. Local anaesthetics behave in a manner similar to that of tetrodotoxin in enhancing cerebral anaerobic glycolysis. 10. Sodium Amytal has a marked effect at relatively high concentration. 11. Tetrodotoxin diminishes efflux of amino acids, particularly glutamate and aspartate, at the onset of anoxia.

Effect of the developmental state of the host guinea-pig on the feeding activity of the tsetse fly Glossina pallidipes Aust.

Individuals of Glossina pallidipes Aust. were reared separately on five developmental categories of guinea-pigs (infants, suckling mothers, pregnant females, mature virgin females, and mature males), from the time of adult emergence until they died, at 22±1°C and 40±5%r.h. More than 70% of the tsetse flies reared on infant guinea-pigs or on suckling mothers died within the first 10 days, before they reached sexual maturity. Of those reared on mature male guinea-pigs, 50% lived for more than 50 days.Pregnant female and mature male guinea-pigs were the most favoured hosts for tsetse feeding: more than 90% of the flies exposed to these two classes of hosts succeeded in feeding, while only 61%, 70%, and 76%, respectively, of those exposed to infants, suckling mothers, and mature virgin females actually fed.

Attachments of infant guinea pigs

Infant guinea pigs were “exposure-trained” with either a rotating striped cube or a tennis ball When they were tested later for choice between the cube and the ball, the animals were found to spend more time near the object with which they had been “trained.” A total training period of 20 min proved to be just as effective as one of 4h. Control animals, exposed to an empty training pen, preferred the cube.

Effect of ischemia on metabolism of the brain of the newborn mouse.

Effect of ischemia on metabolism of the brain of the newborn mouse.