Suitability of laboratory animals for screening anti-hyperlipidemic agents

The present study was undertaken to evaluate and compare the lipid profiles of various laboratory animals to that of human beings. The human subjects and animals included in the study were from three age groups based on key physiological states. A record of the usual dietary constituents and their daily consumption was maintained. The results indicated that the lipid profile of pigs and dogs bears similarity to that of human beings. Results also revealed that lipid profile was labile in the second group of these animals indicating that this age is suitable to bring about the required changes to produce a hyperlipidemic animal.     

Effect of hypotensive agents on baroreceptor reflexes in waking animals

The effect of -methyldopa, clonidine, pentobarbital sodium, and reserpine on reflex bradycardia induced by an artificial rise of the systemic arterial pressure (BP) was studied in experiments on waking cats. The substances used, which have a tranquilizing action, led to various changes in function of the baroreceptor reflexes, the initial BP level, and the cardiac frequency.Department of Experimental Physiology and Pharmacology, Central Research Laboratory, Academician I. P. Pavlov First Leningrad Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 2, pp. 166–168, February, 1979.     

Behavioral effects of phosphatidylserine in aged rats

The behavioral effects of 5 days of administration of phosphatidylserine (PS) was studied in aged rats. The intraperitoneal (5, 10, and 20 mg/kg) or intracerebroventricular (5, 10, and 20 μg/2 μl) injection of PS liposomes caused a facilitated acquisition of active avoidance behavior as studied in shuttle-box and pole jumping test situations. The retention of active and passive avoidance responses was also improved. No substantial difference between PS-treated and control animals was apparent either in the responsiveness to electrical footshock or in the motor activity tested in an open field. Grooming behavior appeared to be enhanced in rats treated with the highest dose of the substance. Since PS affects both central catecholaminergic and cholinergic transmission, which is known to be impaired in old animals, the possibility that the behavioral effects of PS involve brain dopamine and/or acetylcholine systems is discussed.     

Behavioral effects of handling rabbits in infancy

Dutch-belted and Florida White rabbit pups were handled on Days 1 to 20 of life in a fashion similar to that used in handling rats. In addition, the rabbit doe was locked out of the cage for 22 hr daily to minimize social interaction with her young. The doe was excluded from the nest box and her young until an hour after handling, by which time the pups were in a quiescent state. The objective of this experiment was to determine whether handling effects could be obtained in the rabbit when there was no interaction of the mother with her pups immediately subsequent to the handling experience. Handling was found to increase open-field activity in both strains. Handling also had a strong effect in increasing the exploratory behavior of the Dutch-belted rabbit; the handled Florida White rabbit explored more as well, but the magnitude of difference was less than that found with the Dutch-belted strain. The Dutch-belted rabbits approached and spent more time near a stimulus rabbit than did their controls, while no difference was obtained with the Florida White strain. These findings, in conjunction with other experimental data, strongly argue that handling in and of itself brings about differences in behavior independent of any maternal interaction with the pups. In addition, the results with the rabbits are remarkably similar to the results obtained with rats, suggesting that the handling technique has broad interspecies generality.     

Behavioral effects of bombesin administration in rats

Bombesin (BBS, 0.1–0.4 μg) administered to the lateral cerebral ventricle (IVT) of rats decreased food intake and feeding behavior. Grooming behavior increased and resting behavior decreased at doses ?0.01 μg. IVT BBS (4.0 μg) caused greater suppression of food-deprivation-induced food intake and feeding behavior than the same dose and volume administered intraperitoneally (IP). After IVT BBS, rats displayed more grooming and less resting than normal, but after IP BBS, rats displayed a normal frequency of grooming and more resting. IVT BBS (?0.01 μg) also decreased drinking behavior, and drinking-associated feeding, and suppressed (?0.1 μg) water-deprivation-induced water intake. When neither food nor water was present, non-deprived rats displayed increased grooming and decreased resting after IVT BBS (1.0 μg). The results show that IVT BBS inhibits feeding markedly, but the inhibition of feeding by IVT BBS does not resemble normal satiety or the effect of IP BBS because the central inhibition of feeding is always accompanied by excessive grooming and little resting. Furthermore, since IVT BBS decreases drinking at a dose lower than that required to reduce food intake, and IP BBS does not, the specific satiety effect of IP BBS on feeding cannot be mediated solely by increasing bombesin in the cerebrospinal fluid.     

Antiproliferative effects of cannabinoid agonists on deep infiltrating endometriosis

Deep infiltrating endometriosis (DIE) is characterized by chronic pain, hyperproliferation of endometriotic cells and fibrosis. Since cannabinoids are endowed with antiproliferative and antifibrotic properties, in addition to their psychogenic and analgesic effects, cannabinoid agonists have been evaluated in DIE both in vitro and in vivo. The in vitro effects of the cannabinoid agonist WIN 55212-2 were evaluated on primary endometriotic and endometrial stromal and epithelial cell lines extracted from patients with or without DIE. Cell proliferation was determined by thymidine incorporation and production of reactive oxygen species by spectrofluorometry. ERK and Akt pathways were studied by immunoblotting. Immunoblotting of α-smooth muscle actin was studied as evidence of myofibroblastic transformation. The in vivo effects of WIN 55212-2 were evaluated on Nude mice implanted with human deep infiltrating endometriotic nodules. The in vitro treatment of stromal endometriotic cells by WIN 55212-2 decreased cell proliferation, reactive oxygen species production, and α-smooth muscle actin expression. The decrease in cell proliferation induced by WIN 55212-2 was not associated with a decrease in ERK activation, but was associated with the inhibition of Akt activation. WIN 55212-2 abrogated the growth of endometriotic tissue implanted in Nude mice. Cannabinoid agonists exert anti-proliferative effects on stromal endometriotic cells linked to the inhibition of the Akt pathway. These beneficial effects of cannabinoid agonists on DIE have been confirmed in vivo.     

Behavioral effects of experimental maternal hyperphenylalaninemia

Biochemical and behavioral effects of pre- and postpartum hyperphenylalaninemia were evaluated on 52 Sprague-Dawley rats. Biochemical results indicated elevated plasma phenylalanine levels during both the prepartum (Gestation Days 15-21 and postpartum Days 1-60 of age) injection phases. Behaviors were evaluated beginning at 81 days of age. Compared to control or postpartum subjects, prepartum subjects demonstrated significant decrements on each of the following: initial DRL: 12 learning; fearfulness (inverse relationship); activity; exploration; and sociability. Compared to controls, postpartum subjects were significantly less active and less exploratory.     

Behavioral effects of intracerebroventricular injection of oxytocin in birds

In addition to playing a role as a hormone, oxytocin (OT) can act as a neurotransmitter. In birds, mesotocin (MT) replaces OT. There is both direct and indirect evidence for behavioral effects of OT in rats and humans, but there have been no such studies performed in birds. The purpose of this study was to define the effect of intracerebroventricular (i.c.v.) injection of OT (0-10 microg) on locomotion and feeding behaviors of broiler cockerels. Stepping and wing flapping were increased dose-dependently, but OT decreased preening. The i.c.v. injection of OT also caused a dose-dependent decrease in feed intake, feeding time and pecking frequency. These results suggest that OT might play a unique role in inducing a state of arousal in chickens that resembles fear/anxiety and also in reducing feed intake by acting on MT and/or vasotocin receptors.     

Perinatal methylmercury intoxication: Behavioral effects in rats

Sprague-Dawley rats were subjected to perinatal (4th gestational day until Postnatal Day 21) methylmercury intoxication to determine the long-term behavioral effect of the mercury poisoning. Experimental and control animals were evaluated at 110–140 days of age. Compared to controls, the methylmercury animals demonstrated significant behavioral deficits characterized by hypoactivity and by reduced appetitive, escape, and avoidance learning.     

Behavioral effects of ethynyl estrogens in the female rat

The synthetic analogues of estradiol, ethynyl estradiol and mestranol, are used in oral contraceptives. Their effects on food intake and sexual behavior were evaluated in female rats, and compared with those of estradiol. It was found (Experiment 1) that both ethynyl estradiol and mestranol reduced food intake reliably, and more than estradiol. Water intake and body weight followed similar trends. Ethynyl estradiol, but not mestranol, plus progesterone stimulated proceptive and receptive behavior in ovariectomized female rats. Daily administration of ethynyl estrogens without progesterone showed similar trends (Experiment 3). It is hoped that these studies provide guidelines for further work on the effects of synthetic estrogens on sub-primate and primate behavior.     

Behavioral effects of iron deficiency in the adult rat

Adult hooded rats were placed on an iron deficient diet for 2 (Stage 1), 8 (Stage 2) or 12 (Stage 3) weeks. Iron levels were monitored by a number of indices, including hemoglobin concentration, serum iron level, transferrin saturation, total and latent iron binding capacity and brain and liver nonheme iron level. All three dietary conditions yielded depressed hemoglobin levels. The most significant observation was a marked reduction in liver and brain iron levels for Stage 1 animals. All animals were trained on a single trial taste-aversion task. The taste of saccharin solution was paired with either an immediate or delayed intragastric injection of lithium chloride. Memory for the association was measured 24 hr or 4 days after training and was found to be significantly below normal for Stage 1 and not significantly different from normal for either Stage 2 or Stage 3 animals. Learning remained at normal levels and was even enhanced at some stages of deficiency (Stages 2 and 3). Activity levels decreased with increasing iron deficiency. There appeared to be a direct association between memory for the taste aversion task and liver and brain iron levels.     

Behavioral effects of developmental lead exposure in rhesus monkeys

Postnatal lead exposure has been found to cause long-term learning and memory deficits in monkeys. Pulse-chronic exposure, consisting of acute high-level exposure followed by chronic lower-level exposure, has been particularly effective in causing these impairments. We investigated possible antecedents of lead-induced cognitive dysfunction by evaluating the behavioral effects of pulse-chronic lead exposure in rhesus monkeys during the first 6 months of postnatal life. Blood lead concentrations in the monkeys reached a peak of 55.8 +/- 7.8 ug/dl during week 5 after birth and then averaged between 33.1 and 42.9 ug/dl during the rest of the first 6 months after birth. Zinc protoporphyrin levels were increased by lead exposure, but hematocrits were unaffected. Significant lead-related effects were detected on a visual exploration test and a neonatal behavioral assessment battery. Lead-treated monkeys exhibited decreased looking behavior on the visual exploration test and decreased muscle tonus and increased arousal or agitation on the behavioral assessment battery. No effects were seen on a Piagetian object permanence task and no toxic effects on health or growth were detected. In addition to providing indices of behavioral dysfunction during postnatal lead exposure, performance on these early behavioral tests may predict later lead-induced cognitive dysfunction.