Effects of olfactory bulbectomy and peripheral deafferentation on reactions to crowding in gerbils (Meriones unguiculatus).

Conducted tests of 90 male weanling Mongolian gerbils which sustained either olfactory bulbectomies, surgical ablation of olfactory receptors, or sham operations, and lived in 1 of several density conditions for 2 mo. Differential density conditions significantly affected only sham Ss. All anosmic Ss showed deficiencies in social-interaction tests. Only bulbectomized crowded Ss showed extreme aggression in the home cage. Olfaction is shown to be an important factor mediating deleterious effects of crowding. However, since the presence of the bulbs in receptor-ablated Ss was sufficient to control home-cage aggression, that displayed by bulbectomized crowded Ss cannot be attributed to mere anosmia but rather to loss of a nonolfactory, limbic function of the bulbs. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of selective social buffering of the plasma cortisol response in laboratory-reared male guinea pigs (Cavia porcellus).

The authors examined the effect of different classes of females on the plasma cortisol response of male guinea pigs (Cavia porcellus) from shortly after weaning through full adulthood. Males housed under standard laboratory conditions with artificial harems of 2 unrelated females of similar age were tested at 4 age ranges (~Days 40, 120, 180, and 240). At each age range, males were placed into a novel environment for 2 hr on 4 separate occasions: while alone, with 1 female cage mate, with the other female cage mate, or with an unfamiliar female. Relative preference for the 2 female cage mates was determined from observations in the home cage. Puberty was estimated by plasma testosterone levels. At the 3 youngest ages, the more preferred, less preferred, and unfamiliar females did not differentially reduce the plasma cortisol response. At 240 days of age, only the presence of the more preferred female was able to significantly reduce cortisol levels. These results demonstrate a very selective social buffering effect on the plasma cortisol response in a nonmonogamous species. This effect emerges well after sexual maturity and can be observed under standard laboratory housing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pressor effects elicited by stimulation within the medullary raphe nuclei of the guinea pig (Cavia porcellus)

A series of 120 pathologically verified intraspinal tumors was analyzed for the relative incidence and location of the tumors as well as the distribution of age and sex. These data were compared to series from Taiwan, mainland China, Thailand, Korea, Japan, Iran, India, and countries in the West. The ratio of brain to intraspinal tumors was about 5:1 in Taiwan, higher than those reported in China, Korea, and in the West. The male to female ratio is about six to five. For most tumors, male predominance is noted except for meningioma. The incidence of intraspinal tumors in the order of frequency is nerve sheath cell tumor(NSCT), metastatic tumors, meningioma, glioma, congenital tumors, and vascular tumors. In the East, the incidence of NSCT is about 40%, and meningioma is about 10%. In the West, they are both about 20%. Congenital tumors accounted for only 3.3%. In China, it was about 12% and this is the highest incidence of dysembryoplastic tumors in the world. Glioma has similar incidence (about 10%) in Taiwan, China, Thailand, Japan, and Iran (about 10%), whereas it is about 15% in the West and India. Korea has the highest incidence of glioma, (32.3%). Low incidences of metastatic intraspinal tumors (4.6-5.5%) were noted in China and Japan, but a higher incidence (14.2-24.2%) was seen in Taiwan, Iran, and the West. The most common metastatic tumors in the order of frequency is tumors of unknown origin, lung cancer metastasis, hepatoma, and breast cancer. The high percentage of unknown origin of metastasis may have resulted from loss of follow-up and lack of postmortem studies.     

Effects of neonatal (Day 10) olfactory bulb lesions on social behavior of female golden hamsters (Mesocricetus auratus).

Found that, after neonatal (Day 10) bilateral olfactory bulbectomy (BOB; n = 16), adult female golden hamsters' scent marking and defense behavior to males was reduced relative to sham (n = 13) or neocortically lesioned (n = 11) littermate controls. The BOB aggressive and sexual behavior appeared grossly normal-15 were successfully mated, but 5 destroyed their litters. After mating, controls became more aggressive but BOB aggression decreased and had disappeared by the 2nd wk. of pregnancy. All groups ceased scent marking after mating, but controls returned to premating levels during lactation. The BOB Ss showed no scent marking, defense, or aggression throughout lactation. Unilateral olfactory bulbectomy of 6 Ss also eliminated normal social behavior during lactation, suggesting that not all the behavioral effects of olfactory damage can be attributed to anosmia. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of male social status on reproductive success and on behavior in mice (Mus musculus).

Differences in reproduction as well as in behavior in the presence of females were evaluated according to dominant and subordinate male rank in albino mice, in the temporary absence of each male's antagonist. Dominant males reproduced more successfully than subordinate males. Subordinate males were generally inactive, except for displacement activities, during the first 15 min they were exposed to female partners. These findings suggest that mechanisms other than male–male interference or mating order may be operating or influencing behavior and reproductive results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of 5 alpha-dihydrotestosterone and methandrostenolone in male guinea pigs

Young adult guinea pigs were studied 6 and 9 weeks after silastic capsules containing 5 alpha-hydrotestosterone (5 alpha-DHT) and methandrostenolone (Dianabol) were implanted. DHT was more effective in causing testicular atrophy and was apparently more androgenically potent in sustaining the size of the seminal vesicles. Both steroids led to hypertrophy of the masseter muscle and increase in gastrocnemius protein concentration. Cardiac tissue was sensitive to the effects of these steroids, particularly to the larger amounts of absorbed Dianabol, in terms of increases in DNA concentration and transient loss of tissue sodium, potassium, and calcium. All alterations in muscle composition occurred in the total absence of change in tissue water. Hypernatremia and hyperkalemia was present in steroid-treated animals with significant loss of urinary potassium in DHT-treated guinea pigs. Adrenal atrophy and the lowering of circulating cortisol was further indicative of effects upon adrenocortical function and the regulation of electrolyte balance.     

Effects of olfactory bulb ablation and androgen on marking and agonistic behavior in male Mongolian gerbils (Meriones unguiculatus).

Male Mongolian gerbils, selected for high marking frequency, were paired with male opponents, and marking and fighting behavior were recorded. Animals then underwent castration, bilateral bulbectomy, unilateral bulbectomy, the combined operations, or a sham operation; and their behavior was again observed. All operated animals showed drastic reduction in both marking and aggressive encounters. Injections of testosterone propionate (TP) produced complete restoration of marking in castrates, but not in bilaterally or unilaterally bulbectomized animals or combined operates. The exhibition of aggression after injections of TP, however, was enhanced to supernormal levels in bulbectomized or bulbectomized-castrated animals. The results suggest the following: that removal of the olfactory bulbs may eliminate a critical neural input necessary for the normal expression of marking and agonistic behavior; that although marking and fighting are influenced by olfactory input and gonadal steroids, their regulatory mechanisms may not be identical; and that removal of the bulbs may sensitize a neural mechanism controlling aggression, thus potentiating its elicitation following administration of exogenous androgen. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of pre- and postpubertal social experience on sexual and social behavior in male and female brown lemmings (Lemmus sibiricus).

In 3 studies, male and female brown lemmings were either isolated at weaning (18 days) or then housed with siblings for another 10 days before being isolated. Before testing for sexual behavior at the age of 75–103 days, half of each group of males received a series of exposures to estrous females and half of each group of females was housed with a stud male. The results of mating tests indicate that whereas prior sexual experience facilitated subsequent copulatory behavior in both sexes, prepubertal interactions subsequently facilitated contact social and sexual behavior in males but did not increase the behavioral scores of females, who engaged in high levels of sexual behavior regardless of prepubertal experience. The effect of prior copulatory activity on male sexual performance could not be attributed to increasing age (i.e., maturational processes) because the behavior of males tested once but at different ages did not differ appreciably. Prepubertal social interaction appeared to predispose males to benefit from sexual experience later in life. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Copulatory behavior of sexually inexperienced male guinea pigs paired with synchronized estrus females

OBJECTIVE: To determine the number of children in the United States with parents incarcerated in jail and to describe the characteristics of these parents and their criminal histories. SETTING: Inmates of local jails accounting for 36.5% of the incarcerated population of the US in 1989. PARTICIPANTS: Personal interviews with 5675 inmates randomly selected from 393,553 inmates of 3312 local jails in 1989. RESULTS: 44,263 (36%) inmates had children younger than the age of 15. Fathers outnumbered mothers 10-fold; the majority were in their 20s or 30s, unmarried, and poorly educated. The vast majority of parents had a record of prior offenses, and substance abuse accounted for one third of the incarcerations. Substance abuse was reported by 84% of inmates and 95% had sought prior treatment for alcohol, drug, or other mental health problems. CONCLUSIONS: Nearly 1 of 50 children in the US has a parent in jail. Parental imprisonment is not rare, is often chronic, and is strongly associated with other psychosocial and health problems in the family. Screening for parental imprisonment potentially should be included as part of a comprehensive biopsychosocial assessment.     

Formamide denaturation of chromosomal DNA for in situ hybridization and c-band preparation in the guinea pig, Cavia porcellus

1. Protein disulphide-isomerase and glutathione-insulin transhydrogenase activities were assayed in parallel through a conventional purification of protein disulphide-isomerase from ox liver. 2. Throughout a series of purification steps (differential centrifugation, acetone extraction, (NH4)2SO4 precipitation and ion-exchange chromatography), the two activities appeared in the same fractions but were purified to different extents. 3. The final sample was 143-fold purified in protein disulphide-isomerase but only 10-fold purified in glutathione-insulin transhydrogenase; nevertheless the two activities in this preparation were not resolved by high-resolution isoelectric focusing and both showed pI4.65. 4. In a partially purified preparation containing both activities, glutathione-insulin transhydrogenase was far more sensitive to heat denaturation than was protein disulphide-isomerase; conversely protein disulphide-isomerase was more sensitive to inactivation by deoxycholate. 5. The data are inconsistent with a single enzyme being responsible for all the protein disulphide-isomerase and glutathione-insulin transhydrogenase activity of ox liver. It is suggested that several similiar thiol-protein disulphide oxidoreductases of overlapping specificities may better account for the data.     

Induction of female and male mating patterns in female rats by gonadal steroids: Effects of neonatal or adult olfactory bulbectomy.

Three experiments evaluated hormonally mediated sexual response patterns in Long-Evans female rats receiving olfactory bulb ablations neonatally (Day 2) or in adulthood. In a test of Ss' reactivity to a caged male in an open field, estrogen and progesterone treatments increased the number of squares entered and the number of cage contacts, but olfactory bulb removal had no effect on these measures. During mating tests, the feminine sexual behavior of Ss' bulbectomized on Day 2 was similar to that of control-operated Ss, whereas Ss bulbectomized as adults displayed enhanced levels of lordosis, darting, and ear wiggling. Lordosis varied with estrogen dose, whereas darting was progesterone-dependent. In tests of masculine copulatory behavior, the proportion of bulbectomized Ss (Day 2 and adult) that mounted was significantly lower than that of control-operated Ss. The effects of olfactory bulb removal, which vary with the age at ablation and the behavioral system investigated, are not mediated by a single neuroendocrine system and cannot be interpreted in terms of a unitary "arousal" construct. (54 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of novelty on the reproductive behavior of male Japanese quail (Coturnix coturnix japonica).

In Exp I, 8 sexually deprived male Japanese quail were exposed to 1 of 7 female Japanese quail until they satisfied a 20-min sexual satiation criterion. The female was then replaced with a novel female or was allowed to remain in the test cage undisturbed. Introduction of the novel female did not reinvigorate sexual behavior above levels observed when the female was allowed to remain undisturbed. In Exp II, with 9 males and 15 females, males that were not sexually deprived were tested in the presence of 2 females. During experimental tests, 1 of the females was novel and the other was familiar. During control tests, both of the females were familiar. The presence of a novel female increased overall levels of male sexual behavior and also increased the number of males engaged in reproductive behavior. However, the enhanced sexual behavior was not differentially directed toward the novel or familiar female. Implications of these findings for the mating system of Japanese quail and for studies of the role of novelty in sexual behavior are discussed. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of humidity on reproductive behavior in male and female zebra finches (Taeniopygia guttata).

Zebra finches (Taeniopygia guttata) are regarded as opportunistic breeders with reproductive behaviors mediated by short-term proximal environmental conditions. This article provides experimental evidence for the role of humidity in reproductive behaviors. Zebra finches were subjected to experimentally manipulated high levels of relative humidity. Males gathered more nest material and sang more. Females showed no relationship between humidity and gathering nest materials, egg laying, or changes in rates of vocalization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of male pre-ejaculatory vocalizations on female receptive behavior in the rat (Rattus norvegicus).

Both male and female rats (Rattus norvegicus) emit ultrasounds during copulation. Bursts of ultrasounds from males that occur as ejaculation approaches are lower in frequency, longer in duration, and louder than those that appear earlier in the ejaculatory series. We attempted to determine if these pre-ejaculatory calls affect female sexual behavior. The behavior of females paired with devocalized males was compared with that of females paired with intact males, and in a second experiment tape-recorded vocalizations were played to females paired with devocalized males. Females were less receptive when paired with devocalized males; they were less likely to remain stationary when males attempted to mount. Playback of both types of calls restored female immobility toward control levels, although pre-ejaculatory calls were more effective than mating ones. Pre-ejaculatory calls restored running and trailing levels somewhat toward control level but to a lesser extent than female immobility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photoperiodic and endocrine control of social proximity behavior in male Japanese quail (Coturnix coturnix japonica).

Experiment 1 demonstrated that the social proximity behavior of male Japanese quail declines significantly when photostimulation is restricted to 2 hr daily, but can be restored by reinstituting the normal schedule. Changes in the photoperiod produced corresponding changes in the size of the cloacal gland, an androgen-dependent organ. The low levels of social proximity behavior and cloacal gland size of males maintained on short daily exposures to light also could be reversed by sc implants of testosterone (Experiment 2), and this recovery was to some extent sensitive to testosterone dose (Experiment 3). The present studies indicate that social proximity behavior in male Japanese quail is androgen dependent and provide a behavioral assay for neurohormonal studies of sexual behavior that does not depend on brief phasic responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of thalamic and olfactory cortical lesions on continuous olfactory delayed nonmatching-to-sample and olfactory discrimination in rats (Rattus norvegicus).

We conducted 2 studies to determine the importance of several brain systems for remembering odorants in a go/no-go delayed nonmatching-to-sample (DNMTS) task. In Experiment 1, impairments were observed for lesions of pyriform cortex or (to a lesser extent) the lateral internal medullary lamina of thalamus. Lesions of the entorhinal cortex or the mediodorsal (MDn) or the paracentral and centrolateral (PC-CL) thalamic nuclei did not affect DNMTS. In Experiment 2, an impairment comparable to the pyriform lesion was observed for a lesion of the intralaminar nuclei (PC-CL plus the central medial nucleus) but not for a larger lesion of MDn. None of the lesions in either study affected the ability to learn a 2-choice odor discrimination using go/no-go procedures comparable with the DNMTS task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrimination among colony mates' anogenital odors by guinea pigs (Cavia porcellus).

Three experiments used an aversively motivated learning task to examine the ability of adult guinea pigs to discriminate among odors from nonspecific anogenital swabbings of colony mates. Exps I and II examined the ability of 8 male (M) and 8 female (F) Ss to discriminate among odors of colony mates controlled for age and sex. Both sexes were able to discriminate among individual Ss on the basis of odor. Since individual Ss could be discriminated, Exp III, examining detection of physiological estrus, tested the ability of 6 Ms and 6 Fs to discriminate preserved odor samples from the same F during conditions of estrus and nonestrus. Both Ms and Fs were able to discriminate between the conditions. Results are discussed with reference to the involvement of odor in the social behavior of guinea pigs. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of apafant on PAF-induced downregulation of beta-adrenoceptors in guinea pigs

The phase S ratio in cell cycles were analyzed in livers with hyperplastic foci (HPF) and in livers without HPF by nuclear DNA determinations using flow cytometry, and by staining with argyrophilic proteins of the nucleolar organizer region (AgNOR). Flow cytometric analysis was done on 50 fresh frozen specimens of livers resected from 50 patients with hepatocellular carcinoma (HCC). Paraffin sections from the same patients were analyzed using AgNOR staining. There were 25 cases each with and without HPF. We examined the stage of fibrosis and the grade of inflammatory activity according to the modified Scheuer and Desmet scale. The incidence of HCC recurrence among these patients was also studied. The average phase S ratio of the livers of the patients with HPF was 6.5 +/- 3.2%, and that of the livers of the patients without HPF was 4.0 +/- 2.5%. The ratio differed significantly between the two groups (P < 0.01). The average AgNOR score for HPF lesions of the HPF-positive cases was 1.60 +/- 0.34, that for non-HPF lesions in the HPF-positive cases was 1.29 +/- 0.12, and that for the HPF-negative cases was 1.19 +/- 0.14. Significant differences were found between the average AgNOR scores for HPF lesions of the HPF-positive cases and the non-HPF lesions of the HPF-positive cases (P < 0.01), as well as between the non-HPF lesions in the HPF-positive cases and the HPF-negative cases (P < 0.05). Severe fibrosis (stage 3) and cirrhosis (stage 4) were found in 76% of HPF-positive cases and 48% of HPF-negative cases. The livers of HPF-positive patients were significantly more cirrhotic than those of HPF-negative patients (P < 0.05). The association between HPF and the inflammatory grade was not significant (P > 0.05). The incidence of HCC recurrence among HPF-positive cases was significantly higher than that among the HPF-negative cases (P < 0.05). The average phase S ratio of the recurrent HPF-positive patients was 7.48 +/- 3.48%, significantly higher than that of HPF negative cases (5.57 +/- 3.06%, P < 0.05). Hyperplastic foci of the liver was shown to be a highly proliferative lesion. The proliferative activity of the non-HPF lesions in the HPF-positive patients was also higher than that of the HPF-negative patients. Hyperplastic foci tended to be present in cirrhotic livers, but it was not associated with the grade of inflammatory activity of the liver. Hyperplastic foci may represent an important predictor of recurrence after hepatic resection.     

Effects of ethanol intake on the immune system of guinea pigs

Groups of guinea pigs were maintained with alcohol solutions not sufficient to result in liver dysfunction prior to and during investigations designed to determine whether ethanol would nonetheless impair cell-mediated or humoral immunity. No impairment of either was observed in any of the experimental groups.     

Sexual free behavior in male rats (Rattus norvegicus).

Male rats ( Rattus norvegicus) were given continuous access to estrous female rats for 24 hrs each day for 10 days. During the 1st 12 hrs, the rats achieved an average of 10 ejaculations, followed by a 1- to 2-day period with little sexual activity. During the last 7 days, the rats maintained a reasonably stable equilibrium level of 3 ejaculations per day. These occurred predominantly during the dark phase of the diurnal cycle, they frequently occurred in a cluster, and they usually occurred shortly after the introduction of a novel estrous female. Except for quantitative differences, these results are generally consistent with conventional research but systematically extend the generality of the results to the context of the free behavior situation. The availability of sexual activity had no appreciable effect on food and water intake, but it did decrease the amount of running activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)