Is Seeing Believing? Hallmark Movie Viewership and Relationship Beliefs.

The Hallmark Channel, a highly watched cable network, is known for its consistently idealistic portrayals of romantic relationships. Despite its popularity, no research has examined whether increased viewership of Hallmark movies covaries with endorsement of relationship beliefs. According to cultivation theory, what we watch impacts our beliefs and perceptions of reality. Additionally, the Differential Susceptibility to Media Effects Model (DSMM) proposes that certain variables, such as developmental (i.e., age, relationship length) and dispositional factors (e.g., attachment style, gender), may make certain viewers more or less susceptible to the effects of media viewership. Based on this grounding, the main purpose of this study was to determine if watching more Hallmark movies is associated with endorsing certain beliefs about romantic relationships and opposite-sex friendships when controlling for several susceptibility factors. A nationwide sample of heterosexual, married participants (N = 279) completed measures of Romantic Beliefs, Implicit Theories of Relationships, and beliefs about opposite-sex friendships and reported on their media consumption. More frequent Hallmark movie viewership was associated with increased endorsement of several relationship beliefs, above and beyond susceptibility factors (e.g., attachment, relationship length) and daily television consumption. Specifically, greater Hallmark movie viewership was positively associated with greater endorsement of multiple unrealistic relationship beliefs, destiny beliefs, and believing that opposite-sex friendships are problematic. The findings of the current study provide further support for cultivation theory and DSMM.

Effects of neonatal fentanyl on late adolescent opioid-mediated behavior.

Introduction: Because of the steady increase in the use of synthetic opioids in women of childbearing age, a large number of children are at risk of exposure to these drugs prenatally or postnatally through breast milk. While there is older literature looking at the effects of morphine and heroin, there are relatively few studies looking at the long-term effects of high-potency synthetic opioid compounds like fentanyl. Thus, in the present study, we assessed whether brief exposure to fentanyl in male and female rat pups during a period roughly equivalent to the third trimester of CNS development altered adolescent oral fentanyl self-administration and opioid-mediated thermal antinociception. Methods: We treated the rats with fentanyl (0, 10, or 100 µg/kg sc) from postnatal day (PD) 4 to PD 9. The fentanyl was administered daily in two injections given 6 h apart. After the last injection on PD 9, the rat pups were left alone until either PD 40 where they began fentanyl self-administration training or PD 60 where they were tested for morphine- (0, 1.25, 2.5, 5, or 10 mg/kg) or U50,488- (0, 2.5, 5, 10, or 20 mg/kg) induced thermal antinociception. Results: In the self-administration study, we found that female rats had more active nose pokes than male rats when receiving a fentanyl reward but not sucrose alone solution. Early neonatal fentanyl exposure did not significantly alter fentanyl intake or nose-poke response. In contrast, early fentanyl exposure did alter thermal antinociception in both male and female rats. Specifically, fentanyl (10 µg/kg) pre-treatment increased baseline paw-lick latencies, and the higher dose of fentanyl (100 µg/kg) reduced morphine-induced paw-lick latencies. Fentanyl pre-treatment did not alter U50,488-mediated thermal antinociception. Conclusions: Although our exposure model is not reflective of typical human fentanyl use during pregnancy, our study does illustrate that even brief exposure to fentanyl during early development can have long-lasting effects on mu-opioid-mediated behavior. Moreover, our data suggest that females may be more susceptible to fentanyl abuse than males.

Effects of repeated RU 24969 treatment on the locomotor activity, motoric capacity, and axillary temperatures of male and female preweanling rats.

Serotonin (5-HT) 1A and 1B receptors have been implicated in behavioral sensitization, but adult rats appear to develop tolerance to RU 24969 (a 5-HT1A/1B receptor agonist) rather than a sensitized response. The purpose of the present study was to determine whether a one- or four-day pretreatment regimen of RU 24969 would cause sensitization or tolerance in male and female preweanling rats. Depending on experiment, rats were pretreated with RU 24969 (0, 2.5, or 5 mg/kg) for 1 or 4 days (PD 17-20), while testing with lower or higher doses of RU 24969 occurred on PD 22. Locomotor activity, motoric capacity, and axillary temperatures were recorded. The role of Pavlovian contextual conditioning was assessed by administering RU 24969 to rats in either the home cage or a novel environment. On the first pretreatment day, RU 24969 caused both an increase in forward locomotion and motoric impairment, along with a substantial decrease in axillary temperatures. Repeated treatment with the same dose of RU 24969 caused all three dependent measures to show a tolerance response. When given a higher dose of RU 24969 on the test day, the responses lost due to repeated drug treatment were fully (locomotor activity) or partially (motoric capacity and axillary temperatures) reinstated. There was no evidence of behavioral tolerance. Results are consistent with the hypothesis that a subsensitivity of 5-HT1A/1B receptors is at least partially responsible for the tolerance caused by RU 24969, but dispositional tolerance cannot be excluded as a contributing factor.

Effects of dopamine and serotonin synthesis inhibitors on the ketamine-, d-amphetamine-, and cocaine-induced locomotor activity of preweanling and adolescent rats: sex differences.

The pattern of ketamine-induced locomotor activity varies substantially across ontogeny and according to sex. Although ketamine is classified as an NMDA channel blocker, it appears to stimulate the locomotor activity of both male and female rats via a monoaminergic mechanism. To more precisely determine the neural mechanisms underlying ketamine's actions, male and female preweanling and adolescent rats were pretreated with vehicle, the dopamine (DA) synthesis inhibitor ∝-methyl-DL-p-tyrosine (AMPT), or the serotonin (5-HT) synthesis inhibitor 4-chloro-DL-phenylalanine methyl ester hydrochloride (PCPA). After completion of the pretreatment regimen, the locomotor activating effects of saline, ketamine, d-amphetamine, and cocaine were assessed during a 2 h test session. In addition, the ability of AMPT and PCPA to reduce dorsal striatal DA and 5-HT content was measured in male and female preweanling, adolescent, and adult rats. Results showed that AMPT and PCPA reduced, but did not fully attenuate, the ketamine-induced locomotor activity of preweanling rats and female adolescent rats. Ketamine (20 and 40 mg/kg) caused a minimal amount of locomotor activity in male adolescent rats, and this effect was not significantly modified by AMPT or PCPA pretreatment. When compared to ketamine, d-amphetamine and cocaine produced different patterns of locomotor activity across ontogeny; moreover, AMPT and PCPA pretreatment affected psychostimulant- and ketamine-induced locomotion differently. When these results are considered together, it appears that both dopaminergic and serotonergic mechanisms mediate the ketamine-induced locomotor activity of preweanling and female adolescent rats. The dichotomous actions of ketamine relative to the psychostimulants in vehicle-, AMPT-, and PCPA-treated rats, suggests that ketamine modulates DA and 5-HT neurotransmission through an indirect mechanism.