Golden Hamsters Mesocricetus Auratus Research Articles

Day–night rhythm of 5-methoxytryptamine biosynthesis in the pineal gland of the golden hamster (Mesocricetus auratus)

5-Methoxytryptamine is a potent agonist of presynaptic 5-hydroxytryptamine autoreceptors modulating serotonin release in the central nervous system. This methoxyindole can be synthesized in the pineal gland, but its presence in vivo is still controversial, probably because of rapid catabolism by monoamine oxidase. An improved high-pressure liquid chromatography method, with coulometric detection, has been developed for the simultaneous measurement of melatonin, 5-methoxytryptamine, 5-methoxytryptophol and 5-methoxyindolacetic acid. We have demonstrated a day-night rhythmicity in the amount of 5-methoxytryptamine in the pineal gland of golden hamsters (Mesocricetus auratus) maintained under a long photoperiod (14 h light: 10 h darkness) and pretreated with the monoamine oxidase inhibitor pargyline. Levels of 5-methoxytryptamine were highest at 16.30 h and lowest at 00.30 h. The rhythm for 5-methoxytryptamine appears to be the same as for serotonin (opposite in phase to that of melatonin). The identification of 5-methoxytryptamine has been confirmed by analysis with gas chromatography-mass spectrometry.

Single and Concurrent Infections of the Golden Hamster, Mesocricetus auratus, with Echinostoma revolutum and E. liei (Trematoda: Digenea)

Single or concurrent infections of the intestinal trematodes Echinostoma revolutum and E. liei were studied in the golden hamster (Mesocricetus auratus). In single infections, some hamsters were fed 25 +/- 5 metacercarial cysts and others 100 +/- 25 cysts of either E. revolutum or E. liei. In concurrent infections, hamsters were fed simultaneously 20 +/- 5 metacercarial cysts of E. revolutum and 20 +/- 5 cysts of E. liei or 100 +/- 25 cysts each of both trematodes. All hamsters exposed singly to E. revolutum or E. liei were infected. In concurrent infections, 9 of 10 hamsters were infected with both species of echinostomes, and the ratio of E. revolutum to E. liei was 3:1. In single infections, 80% of the E. liei and 60% of the E. revolutum were in the posterior third of the small intestine. In concurrent infections, 80% of the E. liei were in the posterior third and 57% of the E. revolutum in the middle third of the small intestine. The histopathological response of E. liei and E. revolutum in single and concurrent infections showed erosion of intestinal villi with lymphocytic infiltration as the primary response. Extraintestinal echinostomiasis occurred in 2 of the infection groups. Differences in hemoglobin and packed cell volume occurred in the different infection groups.

Play-fighting in the Syrian golden hamster Mesocricetus auratus Waterhouse, and its relationship to serious fighting during postweaning development.

In the Syrian golden hamster Mesocricetus auratus, play-fighting precedes serious fighting during postweaning development, and so may be thought to be a developmental precursor to adult aggression. However, based on both the targets attacked--that is, the cheek pouches during play-fighting and the rump or flanks during serious fighting, and the behavior patterns employed to attack and defend these targets--these two forms of fighting are shown to remain distinct from each other throughout development, even during the ages where they overlap. The decline of play in post-sexually-mature animals is shown to result from an increasing intolerance to contact between animals, and hence greater difficulty in the maintenance of a "playful mood." Therefore, these data show that play-fighting does not grade into serious fighting, and thus does not serve as a developmental precursor to adult aggression.

Effect of the interintromission interval on lordotic response and attack latency in golden hamsters (Mesocricetus auratus).

After 12-15 ejaculatory series, each consisting of several short intromissions (2- to 3-s vaginal penetration) and an ejaculation, male golden hamsters adopt an altered copulatory pattern consisting of long intromissions (5- to 25-s penetration with intravaginal thrusting). Receptivity declines and the tendency for the female to attack the male increases at about the time of this shift in copulatory pattern. Because the mean interintromission interval (III) between short intromissions is about 8 s compared to 100 s between long intromissions, it is possible that females detect this difference and adjust their mating accordingly. When the III between short intromissions from a rested male was experimentally increased to 100 s by use of a halter and lead device, the duration of lordosis was significantly less than that displayed by females paired with control males (8-s III) and virtually the same as that displayed by females paired with males that produced only long intromissions. This suggests that the female uses the temporal patterning of intravaginal stimulation as one criterion for terminating mating with a particular male.

Ancylostoma Ceylanicum: I. Protein and Antigenic Composition of Adult and Larval Stages

The protein and antigenic composition of adult and larval stages of Ancylostoma ceylanicum, a human hookworm maintained in golden hamsters (Mesocricetus auratus), was studied employing immunochemical techniques. SDS-polyacrylamide gel electrophoresis revealed the presence of 47 and 43 protein bands in adult worms and infective larvae respectively in the molecular weight range of 10-170 kD. Crossed immunoelectrophoretic analysis, using immune rabbit sera, showed the presence of 32 antigenic peaks in adults and 19 in infective larval stage. Most of the antigens were common between adult and larval stage as evidenced by cross-line immunoelectrophoresis, although some stage specific antigens were also identified. These studies also demonstrate the complex nature of adult worms as compared to larvae.

Identification of the possible origin of the body target that differentiates play fighting from serious fighting in syrian golden hamsters (Mesocricetus auratus)

Play fighting in the Syrian Golden hamster Mesocricetus auratus can be distinguished from serious fighting by the targets attacked in each case. In play fighting, the animals attack and defend the cheeks and cheek pouches, whereas in serious fighting they attack and defend the rump and lower flanks. Since play typically involves the use of behaviors borrowed from other functional contexts, this paper investigates the origin of the cheek target during play fighting. Comparison of resident-intruder serious fighting with awake and anesthetized intruders does not reveal the cheek to be an inhibited target for serious attack. Similarly, analysis of social investigation and allog-rooming, while revealing the ears to be important targets, do not show the cheeks to be targets in these behaviors. Sniffing, licking, and nibbling of the cheek area appear to occur mainly during sexual encounters by males. This area, seemingly a sexual target, may be the one utilized during play fighting.

Veterinary work with non-domesticated pets. II. Mammals.

Abstract In the previous article features of the more commonly kept non-domesticated pets were discussed and basic requirements for dealing with them in practice were outlined. In this paper small mammals are covered in greater detail with particular attention to the mouse ( Mus musculus ), rat ( Rattus norvegicus ), golden (Syrian) hamster ( Mesocricetus auratus ), mongolian gerbil (jird) ( Meriones unguiculatus ), guinea pig ( Cavia porcellus ), rabbit ( Oryctolagus cuniculus ) and ferret ( Mustela putorius furo ). The first five are all rodents (Order Rodentia), the rabbit is a lagomorph (Order Lagomorpha), and the ferret is a carnivore (Order Carnivora). All will be described under the main headings of biological data, handling and restraint, anaesthesia, and diseases and treatment.

Neuropeptide Y (NPY)-like immunoreactivity in peripheral and central nerve fibres of the golden hamster (Mesocricetus auratus) with special respect to pineal gland innervation

Information on the ambient lighting conditions is conveyed from the retina to the pineal organ by a neuronal pathway involving the suprachiasmatic nucleus (SCN) which acts as a circadian pacemaker. In the hamster, circadian rhythms have been shown to be influenced by injection of neuropeptide Y (NPY) into the SCN. Since NPY-immunoreactive nerve fibres are present in the rat and guinea-pig pineal glands it appeared of interest to investigate the hamster pineal as part of the circadian rhythm generating/regulating system. For comparison kidney, small intestine and cerebral cortex were studied. Like in the other rodent species so far investigated only a few of the abundant sympathetic nerve fibres in the hamster pineal gland are NPY-immunoreactive, in contrast to the relatively rich innervation of the other organs. This speaks in favour of a possible central origin of pineal NPY-immunoreactive fibres. These may either exert vasoregulatory effects on pineal vasculature or be involved in the modulation of alpha-adrenergic receptor mediated regulation of pineal metabolism.

Ancylostoma ceylanicum (Looss, 1911) in golden hamsters (Mesocricetus auratus): pathogenicity and humoral immune response to a primary infection.

The response of hamsters to Ancylostoma ceylanicum was studied between days 13 and 200 after infection. The infected hamsters showed signs of anaemia, particularly between the 13th and 60th days. A significant loss in body-weight in the infected animals was also observed during this period. Serological studies with agar gel-diffusion, counterimmunoelectrophoresis and indirect haemagglutination tests revealed positive reactions between the 20th and 60th days followed by a negative response in the latent period between the 60th and 200th days of infection, counterimmunoelectrophoresis test remained positive for a period of 150 days in this experimental model.

Alpha Tocopherol Alters the Distribution of Langerhans Cells in DMBA-treated Hamster Cheek Pouch Epithelium

Thirty-seven adult male and female golden hamsters (Mesocricetus auratus) were divided into four experimental groups. In Group A, the animals served as untreated controls, having the left buccal pouches painted with mineral oil. In Group B, the animals received 10 mg vitamin E (alpha tocopherol) in peanut oil by the oral route, with a fine pipette, twice weekly. In Group C animals, the left buccal pouch was painted three times weekly with DMBA (0.5% solution of 7,12 dimethylbenz(a)anthracene in heavy mineral oil). Group D animals received both vitamin E and DMBA in the amounts indicated for Groups B and C, with the vitamin E being administered on days alternate to the DMBA painting, also in the manner described for the above groups. All animals were killed after eight weeks of treatment. Epithelial whole mounts were prepared from the left buccal pouches. These specimens were then stained for ATPase to demonstrate the presence of Langerhans cells (LCs). A notably decreased density of LCs was observed after treatment with DMBA. Vitamin E administration in addition to DMBA treatment resulted in a less dramatic decrease in LC density. Since vitamin E has been shown to retard experimental oral carcinogenesis, vitamin E may retard carcinogenesis by maintaining the number of Langerhans cells.

Urine analysis of three rodent species with emphasis on calcium and magnesium bicarbonate

1. 1. The urine composition of three rodent species, mole rat Spalax ehrenbergi, the golden hamster Mesocricetus auratus and the white rat Rattus norvegiens was studied. These three species represent different degrees of fossoriality. 2. 2. The results show that the urine of the species that show a higher degree of fossoriality, the mole rat and the hamster, contain high values of calcium and magnesium bicarbonates when compared with the white rat. 3. 3. From these results it may be assumed that the mole rat as well as the hamster can use the kidney as a pathway for releasing bicarbonate and carbonate. 4. 4. This mechanism may reduce the CO 2 concentration in their hypercapnic environment.

Effects of putative satiety peptides on feeding and drinking behavior in golden hamsters (Mesocricetus auratus).

A series of experiments was conducted to characterize the effects of putative satiety peptides on feeding in the Syrian hamster, a species known to have physiological feeding controls different from those of other animals. Peripheral injections of cholecystokinin octapeptide (CCK-8) reduced feeding in hamsters in a dose-related fashion. CCK-8 was equally effective in reducing food intake in female hamsters tested during the light and dark portions of the illumination cycle but was ineffective in males tested during the light portion. Systemic injections of proglumide, a putative CCK receptor antagonist, did not alter spontaneous food intake and did not reverse the suppression of feeding resulting from peripheral CCK-8 injections. Systemic injections of bombesin (BBS), thyrotropin releasing hormone (TRH), and calcitonin (CT) produced a dose-related suppression of food intake. BBS appeared to do so specifically. In contrast, TRH appeared to reduce feeding by temporarily debilitating the animals; CT, by evoking behavior (increased locomotor activity) incompatible with feeding. Intracerebroventricular (icv) injections of CCK-8, BBS, and CT produced dose-related inhibition of feeding, but only CCK-8 appeared to affect feeding behavior selectively. Reduced feeding after icv BBS was associated with excessive grooming, and icv CT, like systemic CT, increased locomotor behavior. These findings in the hamster are discussed in relation to peptidergic control of feeding in other species.

Determinants of mating success in the golden hamster (Mesocricetus auratus): I. Male capacity.

Rested adult golden hamsters produced a mean of 13 ejaculations and then showed a modified copulatory pattern consisting of long intromissions (10-30 s of intravaginal thrusting) during which no sperm transfer occurs. When a second (fresh) female was introduced, 58% of the males produced at least one more ejaculation, and 17% of the males produced one further ejaculation when placed with a third female. In similar three-female tests conducted 24 hr later, all males ejaculated (M = 4 ejaculations); this level of ejaculatory output was maintained over a subsequent 10-day period of daily testing. Four ejaculations ensured a nearly 100% pregnancy rate and maximum litter size in the first females. Second and third females, however, received fewer ejaculations and subsequently showed reduced fertility and produced smaller litters. Most males showed high levels of long intromissions on all days and with all females. The physiological significance of these long intromissions may be to trigger the progestational response. Examination of the rate of recovery from sexual exhaustion indicated that 2 or 8 hr of rest resulted in fewer than 50% of the males being capable of one further ejaculation. However, most of these single ejaculations were accompanied by long intromissions and resulted in successful pregnancies. Four to eight days were required for full recovery of ejaculatory capacity. This study showed that the male golden hamster has a higher ejaculatory output and more rapid recovery from sexual exhaustion than other small rodents that have been studied. Thus, the limits of male capacity appear to vary widely among species.

Effects of putative satiety peptides on feeding and drinking behavior in golden hamsters (Mesocricetus auratus).

Effects of putative satiety peptides on feeding and drinking behavior in golden hamsters (Mesocricetus auratus).

Hoarding-induced lever pressing in golden hamsters (Mesocricetus auratus): Illumination, time of day, and shock as motivating operations.

Hoarding-induced lever pressing in golden hamsters (Mesocricetus auratus): Illumination, time of day, and shock as motivating operations.

Seasonal variations in the cerebrospinal fluid-contacting area of the pineal gland in the golden hamster (Mesocricetus auratus).

The cerebrospinal fluid-contacting area in the pineal recess of the golden hamster (Mesocricetus auratus) has been investigated light and electron microscopically. The results reveal that in this area the ventricular surface is composed of glial cell processes and protruding pinealocytes. The relative extent of these two components varies considerably and seems to be related to the season of the year: Morphometric analysis shows that in June, the mean size of the total cerebrospinal fluid-contracting area and, in addition, the relative extent of the area occupied by protruding pinealocytes is significantly larger than in November. The physiological significance of this finding remains to be determined.

Intrasexual interactions among female golden hamsters (Mesocricetus auratus) over the estrous cycle.

Intrasexual interactions among female golden hamsters (Mesocricetus auratus) over the estrous cycle.

Exocrine pancreatic secretion in the syrian golden hamster Mesocricetus auratus—III. Effects of carcinogen administration and development of pancreas cancer

1. 1. The short- and long-term effects of the administration of the pancreas carcinogen N-nitrosobis(2-oxopropyl)amine (BOP) on pancreatic exocrine secretion were examined in Syrian hamsters with and without stimulation by secretin and pancreozymin. 2. 2. Protein concentration, flow rate, pH and ion content, (Na +, K +, Ca 2+, Mg 2+, HCO − 3, Cl −, HPO 4 2− and SO 4 2−) were measured. 3. 3. An immediate effect of BOP is the stimulation of flow rate in females and of protein secretion in both sexes. 4. 4. Multiple doses of BOP significantly altered the parameters mentioned in Section 2 only in the later stages of tumorigenesis. When these animals were stimulated with secretin or pancreozymin large decreases in flow rate and protein content of secretions were observed as early as 8 weeks after BOP treatment. 5. 5. Insulin-like immunoreactivity and growth hormone-like immunoreactivity were detected in collected pancreatic secretions.

Day/night rhythmicity in the methylating capacities for different 5-hydroxyindoles in the pineal, the retina and the Harderian gland of the golden hamster (Mesocricetus auratus) during the annual seasons.

In the pineal, the Harderian gland and the retina of the golden hamster the day/night capacity for the synthesis of different methoxyindoles is investigated under natural conditions for one 24-hour period in the months of December, March and June. The amounts of the methoxyindoles and the diurnal rhythms in the synthesis are different in the various months during which the tests were performed. There is a striking increase in the synthesis of melatonin and methoxytryptophol in all three organs in June as compared with December. Equally striking is the high synthesis of methoxytryptamine in the pineal in June, whereas this compound was not formed in the Harderian gland and the retina in this month. Methoxytryptophan synthesis was not observed in June in any of the three organs. Methoxyindoleacetic acid rhythmicity shows a pattern more or less identical to that of melatonin and methoxytryptophol. A high synthesis exists at the end of the June day, but greater fluctuations during the days of the two other months. Acetylmethoxytryptophol is synthesized in the pineal during the night in March, but in the late afternoon in June. The largest quantity of this compound is found in the Harderian gland in December, in the pineal in March and in the retina in June. The largest amounts of melatonin and methoxytryptophol are synthesized when gonadal weight is largest. The possible correlation between the amounts synthesized, the rhythmicities in synthesis and the reproductive system is discussed.

Effects of diet on feeding and body weight regulation during pregnancy and lactation in the golden hamster (Mesocricetus auratus).

The hypothesis was tested that the weight loss shown by lactating hamsters constitutes a "regulated" weight loss. The results support the hypothesis: Prefattened overweight hamsters lost more weight from the time of mating to the end of lactation than did unmanipulated controls. However, the weight loss during lactation was reduced by giving hamsters access to a high-fat diet, a result indicating that a portion of the lactational weight loss may also be regulated by the diet provided. When lactating hamsters were given access to a fractionated diet consisting of pure fat, pure carbohydrate, or 45% protein, they increased their proportional intake of both protein and fat but not of carbohydrate. These studies show that hamsters differ from rats in their pattern of energy regulation during pregnancy, lactation, and the postsuckling period. Reasons for these species differences are discussed.