The role of ovarian hormones in sexual reward states of the female rat.

To what extent does the reward value of sexual stimulation in females depend on ovarian hormones? The effects of estradiol benzoate (EB) and progesterone (P) were examined on the acquisition and expression of sexual reward induced by paced copulation and clitoral stimulation (CLS) in ovariectomized (OVX) rats. In experiment 1 we examined the expression of a pacing-induced conditioned place preference (CPP). Ovariectomized, hormone-primed rats were given experience with paced copulation associated with one side of a CPP apparatus. Changing hormonal status prior to the final CPP test did not alter pacing-induced CPP. However, subsequent partial extinction of CPP was observed only in rats primed with EB+P, a treatment previously shown to induce sexual desire and receptivity. In Experiment 2, significant CLS-induced CPP developed in ovariectomized rats regardless of hormone priming. Our results show that the expression of the sexual reward state induced by paced copulation, and CLS in particular, is independent of hormone priming. We propose that ovarian hormones sensitize sensory and motor pathways necessary for sexual behavior and stimulation to induce reward.

Persistent organic pollutants in plastic marine debris found on beaches in San Diego, California.

Plastic debris were collected from eight beaches around San Diego County, California. Debris collected include: pre-production pellets and post-consumer plastics including fragments, polystyrene (PS) foam, and rubber. A total of n = 2453 pieces were collected ranging from <5 mm to 50 mm in size. The plastic pieces were separated by type, location, and appearance and analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its breakdown products, and chlordanes. PAH concentrations ranged from 30 ng g(-1) to 1900 ng g(-1), PCBs from non-detect to 47 ng g(-1), chlordanes from 1.8 ng g(-1) to 60 ng g(-1), and DDTs from non-detect to 76 ng g(-1). Consistently higher PAH concentrations found in PS foam samples (300-1900 ng g(-1)) led us to examine unexposed PS foam packaging materials and PS virgin pellets. Unexposed PS foam contained higher concentrations of PAHs (240-1700 ng g(-1)) than PS virgin pellets (12-15 ng g(-1)), suggesting that PAHs may be produced during manufacturing. Temporal trends of debris were investigated at one site, Ocean Beach, where storm events and beach maintenance were found to be important variables influencing debris present at a given time.

Sexual behavior in lactating rats: role of estrogen-induced progesterone receptors.

Lactation is associated with suppression of reproductive function, the duration of which depends on the number of young suckled and food availability. Although previous studies have documented increasing responsivity to the positive feedback effects of estrogen on luteinizing hormone (LH) secretion with time postpartum, changes in the ability of estrogen to stimulate sexual behavior across these time points and the influence of food restriction on response to estrogen have not been investigated. Thus, we compared the ability of exogenous estrogen administration to stimulate proceptive and receptive behavior in ad libitum fed and food restricted rats on Days 15 and 20 postpartum. Because the ability of estrogen to induce sexual behavior depends on activation of both estrogen receptors and estrogen-induced progesterone receptors, a second study compared estrogen and progesterone-ir within the VMH and MPOA in similar groups. Finally, we investigated the role of the high levels of progesterone typical of lactation in the suppression of estrogen-induced sexual behavior by transient blockade of the progesterone receptor using RU486. As expected there was an increase across time in the ability of estrogen to stimulate sexual behavior that correlated with an increased ability of estrogen to induce progesterone receptors in the MPOA that was most evident in ad libitum fed rats. RU486 administration concomitant with estrogen administration increased solicitation behavior and was most effective in ad libitum fed rats suggesting an inhibitory role of progesterone on estrogen-induced sexual proceptivity in lactating rats.

Neurochemical basis of conditioned partner preference in the female rat: I. Disruption by naloxone.

The effects of the opioid antagonist naloxone were examined on the development of conditioned partner preference induced by paced copulation in female rats. In Experiment 1, ovariectomized, hormone-primed rats were conditioned to associate scented and unscented male rats with paced and nonpaced copulation, respectively. Female rats in Experiment 2 associated albino or pigmented male rats with paced or nonpaced copulation. Naloxone or saline was administered before each conditioning trial. During a final drug-free preference test, female rats could choose to copulate with either a pacing related or unrelated male. Saline-trained female rats in the paired group copulated preferentially with the pacing-related male rat, whereas naloxone-trained female rats did not show a preference. The authors concluded that opioids mediated the conditioned partner preference induced by paced copulation.

Enfoque fisioterapéutico en pacientes con parálisis facial periférica / Physiotherapy approach in patients with peripheral facial paralysis

La Parálisis Facial Periférica a FRÍGORI O DE Bell, fue descrita por primera vez por el médico inglés Charles Bell, de cuyo apellido toma su nombre.Es una enfermedad aguda que acurre a cualquier edad, detectada con relativa frecuencia en nuestro medio. Aunque se observa generalmente, en personas entre los 15 a 45 años de edad, casi siempre es unilateral con afectación parcial o total del nervio facial en sus posiciones terminales y puede recidivar en algunas ocasiones.Se ha demostrado que existe una tendencia a aumentar en determinadas épocas del año, describiendo su aparición en brotes epidémicos, razón por la cual se la denominó Parálisis Facial Periférica a Frígori, debido a los cambios de temperatura.Cuando se presenta, tanto el paciente como la familia experimentan desconcierto, preocupación e incluso confusión ante una patología cuya etiología es indeterminada y donde la mayoría de las veces no se encuentra explicación. La asimetría facial, la incertidumbre del paciente y la dificultad para escoger una terapia adecuada dentro de varias alternativas, nos obliga a intervenir y ofrecer un tratamiento de rehabilitación global que se origina de la experiencia adquirida.Los sorprendentes resultados de una facilitación en la contracción muscular como tratamiento fisioterapéutico, para la recuperación efectiva y eficaz del paciente, son las principales causas que motivaron la elaboración del presente trabajo.