Fischer 344 (F344) rats may be useful for studying impairments in social interactions because they exhibit reduced play behavior compared to Sprague-Dawley (SD) rats. The purpose of this investigation was to explore F344 rats as a model of early social interaction deficits and to determine if oxytocin (OT) activity mediated attachment behavior. To this end, we conducted three experiments measuring the preference of a dam-paired odor in postnatal day (PD) 12 F344 and SD rats. In Experiment 1, PD 11 pups were conditioned with a dam- or neutral-paired odor and tested for odor preference on PD 12. Experiments 2 and 3 used the same protocol as Experiment 1, except in Experiments 2 and 3, pups received an injection of OT (0, 250, 500, or 1000 ng, IC) or OT antagonist (OTA) (0.1, 0.3, or 1 mg/kg, IP) prior to the start of conditioning. Preference for the dam-paired odor did not differ between rat strains, however both male and female F344 pups showed a greater preference for the maternal odor when treated with OT. Male rats showed this enhanced preference at 500 ng OT while females required 1000 ng OT. OT did not alter odor preference in SD pups and OTA did not alter either rat strain’s preference. In conclusion, F344 rat pups do not have attachment deficits but may be useful for testing compounds to treat attachment disorders. It is possible that maternal attachment differs from other social behaviors, such as play behavior. Exogenous OT administration enhanced attachment but only in F344 rats. These data suggest further research on OT in F344 rats is warranted. In addition, it has been suggested that, since ASD affects more boys than girls, the problem may lie with AVP rather than OT. Therefore, other mechanisms may be involved in the development of social behaviors and perhaps the development of maternal attachment. Further testing of other neurochemicals such as dopamine and AVP as well as examining other stages of development (i.e., adolescence and adulthood) may be useful in identifying new therapeutics for ASD.

No description available.

<p>Massage i skolan kan gå till på många olika sätt, bland annat med hjälp av en massagesaga. Det är viktigt att eleverna själva vill vara med. De ska aldrig tvingas. När man blir berörd utsöndras det ett lugn och ro-hormon i kroppen som heter oxytocin. Det får oss att bli mindre aggressiva och mer avslappnade. Jag har i mitt examensarbete undersökt vilka massagens positiva och negativa effekter är. Jag har intervjuat fem pojkar, som inte vill vara med på massagen, om varför och hur de känner inför densamma.</p>

Experiments were conducted to determine whether endogenous progesterone regulates synthesis and/or secretion of luteal oxytocin (OT). In experiment 1, mature ewes (n=5 per group) were assigned randomly to control or mifepristone (RU 486) treatment groups. Ewes were injected twice daily s.c. with vehicle or 10 mg RU 486 from days 5-7 of the estrous cycle (estrus=day 0). On day 8, following an i.v. prostaglandin F₂α (250 μg cloprostenol) challenge, venous samples were collected at frequent intervals to determine plasma OT concentrations. Plasma OT in RU 486-treated animals did not differ significantly from those of the control animals (P>0.05). In Experiment 2, ewes were injected s.c. daily with vehicle or 175 mg RU 486 from days 2-5 of the estrous cycle followed by a prostaglandin F₂α (250 μg cloprostenol) challenge on day 6. Four of five RU 486-treated ewes exhibited "split-estrus" (estrous behavior through 36 hours and again 84 to 108 hours after the onset of initial estrus). There was no significant difference in mean plasma OT or progesterone levels between treatment groups (P>0.05). Mean mature corpus luteum (CL) weights of control and RU 486-treated ewes on day 6 did not differ (394.8 ± 28.8 vs. 319.5 ± 48.3 mg; P>0.05). Mifepristone-treated ewes contained mature CL, new CL (2 of 4 ewes), and/or preovulatory follicles (≥ 10 mm, 2 of 4 ewes). Average interestrous interval for RU 486-treated ewes was 9 days longer than that of control animals (26.2 ± 2.9 vs. 17 ± 0.5 days; P<0.025). A subsequent study was conducted to determine the effects of gonadotropin-releasing hormone (GnRH)-stimulated release of luteinizing hormone (LH) on luteal OT and progesterone production in beef heifers. Ten heifers with normal estrous cycles were assigned randomly in equal numbers to a control and treatment group. On day 2 of the estrous cycle (estrus=day 0) heifers were injected with either physiological saline or 100 pg GnRH every 4 hours for 56 hours. Samples were collected 0 min pre- and 180 min post-GnRH challenge for progesterone analysis. Sixty hours after the initial injection of GnRH or saline, heifers were challenged with an i.v. injection of 500 pg prostagland in F₂α (cloprostenol) and blood was collected at frequent intervals for OT analysis. Luteal OT synthesis was suppressed (P<0.01) in heifers receiving repeated injections of GnRH compared to saline-treated control animals. Progesterone secretion was significantly greater in saline-treated animals compared to GnRH-treated animals pre- and post-challenge (1.0 ± 0.06 vs. 0.93 ± 0.11 ng/ml and 1.16 ± 0.05 vs. 0.96 ± 0.13 ng/ml, respectively; P<0.05). / Graduation date: 2003

Graduation date: 2003

Graduation date: 1998

Graduation date: 1995

Previous research attests to the relationship between social support and positive health outcomes while linking social isolation or aggression/hostility with negative health outcomes. Several studies examining atherosclerosis with either genetic or behavioral origins, have reported decreased disease severity in socially supportive environments. In order to identify and understand the mechanism responsible for decreased disease, the current study examined physiological differences in New Zealand White rabbits within unstable, stable, and isolated social environments and observed whether functional hormonal changes were apparent over time and as a response to behavior characteristic of these environments. Results indicated that animals within the unstable condition displayed increased agonistic behavior, increased cortisol and epinephrine, decreased body weight, epididymal fat, and retroperitoneal fat, as well as larger spleens. Cortisol values positively correlated with measures of agonistic behavior for all animals, while the reverse relationship was found for affiliative behavior. The novel finding of an increase in oxytocin in animals in the unstable condition within the first ten minutes of pairing that was noticeably distinct from the other two groups suggests that plasma oxytocin levels are related to acute stress. Limitations and interpretations of these findings are discussed. Future work is still needed to help further explain the physiological response to social stress and affiliation and to elucidate the mechanism by which a supportive social environment appears to protect against progression and severity of heart disease.

Massage i skolan kan gå till på många olika sätt, bland annat med hjälp av en massagesaga. Det är viktigt att eleverna själva vill vara med. De ska aldrig tvingas. När man blir berörd utsöndras det ett lugn och ro-hormon i kroppen som heter oxytocin. Det får oss att bli mindre aggressiva och mer avslappnade. Jag har i mitt examensarbete undersökt vilka massagens positiva och negativa effekter är. Jag har intervjuat fem pojkar, som inte vill vara med på massagen, om varför och hur de känner inför densamma.

The naked mole-rat (Heterocephalus glaber) demonstrates a strict social and reproductive hierarchy. Oxytocin (OXT) is a peptide hormone that acts both peripherally and centrally in the regulation of a number of sexual and social behaviours. The main area of central production of this peptide is the paraventricular nucleus of the hypothalamus (PVN). The present study characterized differences that exist in OXT neurons in this region. Breeders and subordinates from established colonies were sacrificed and brains were processed for OXT-immunoreactivity. Four further groups of paired animals underwent various social and hormonal manipulations (opposite-sex paired, same sex-paired, opposite-sex/gonadectomised paired, opposite-sex/vasectomized paired) and were also used for analysis. Results showed that subordinate naked mole-rats had significantly more OXT-immunoreactive neurons in the PVN than either breeders or paired animals that had been gonadectomised. However, no differences were found on measures of OXT cell volume. Possible functional significance of these differences is discussed.