Localizing Brain Regions Associated with Female Mate Preference Behavior in a Swordtail

Female mate choice behavior is a critical component of sexual selection, yet identifying the neural basis of this behavior is largely unresolved. Previous studies have implicated sensory processing and hypothalamic brain regions during female mate choice and there is a conserved network of brain regions (Social Behavior Network, SBN) that underlies sexual behaviors. However, we are only beginning to understand the role this network has in pre-copulatory female mate choice. Using in situ hybridization, we identify brain regions associated with mate preference in female Xiphophorus nigrensis, a swordtail species with a female choice mating system. We measure gene expression in 10 brain regions (linked to sexual behavior, reward, sensory integration or other processes) and find significant correlations between female preference behavior and gene expression in two telencephalic areas associated with reward, learning and multi-sensory processing (medial and lateral zones of the dorsal telencephalon) as well as an SBN region traditionally associated with sexual response (preoptic area). Network analysis shows that these brain regions may also be important in mate preference and that correlated patterns of neuroserpin expression between regions co-vary with differential compositions of the mate choice environment. Our results expand the emerging network for female preference from one that focused on sensory processing and midbrain sexual response centers to a more complex coordination involving forebrain areas that integrate primary sensory processing and reward.     

Surface treatments and cell attachment

Summary Photoelectron spectroscopic examination of treated plastic surfaces showed that surface oxidation, primarily as carboxyl groups, was responsible for formation of good growth surfaces. Gas-plasma studies indicated that only very short exposures were required and that the effect was confined to a thin surface layer that produced adhesive surfaces. Highly adhesive surfaces were produced using oxidizing chemicals. Studies with a polymeric ester demonstrated the importance of unesterified carboxyl groups for high adhesiveness.     

Lactate formation by rat small intestine in vitro

The formation of lactic acid by mucosal slices, rings and muscle from rat jejunum has been studied for periods of up to 8 min. Lactate output by mucosal slices incubated in the absence of glucose was characterised by two phases: a rapid, initial phase of release lasting about 1 min, followed by a much slower phase extending over the remainder of the incubation period. Glucose addition at 30 s initiated a second rapid phase of lactate release into the medium which was again followed by a slower rate of lactate output up to 8 min. The time course of lactate output suggested that there was a negative Pasteur effect in mucosal slices, which could not be reversed by the addition of ADP or glucose 6-phosphate. By contrast, the rate of lactate formation by rings and muscle from rat jejunum increased steadily over the incubation period, indicating a positive Pasteur effect. When Na⁺ in the incubating medium were replaced by K⁺, lactate formation by mucosal slices and rings was considerably reduced. Measurements of tissue lactate content before and during incubation revealed that about three-quarters of the lactate released by mucosal slices during the first 30 s of incubation was present initially in the tissue. After the first 30 s the tissue lactate remained constant both in the presence and absence of glucose so that the lactate released into the incubation medium is equivalent to the lactate formed by the slices. The role of the various tissue components of the small intestine in lactate formation is discussed in relation to sites of glucose entry.     

Surface treatments and cell attachment

Photoelectron spectroscopic examination of treated plastic surfaces showed that surface oxidation, primarily as carboxyl groups, was responsible for formation of good growth surfaces. Gas-plasma studies indicated that only very short exposures were required and that the effect was confined to a thin surface layer that produced adhesive surfaces. Highly adhesive surfaces were produced using oxidizing chemicals. Studies with a polymeric ester demonstrated the importance of unesterified carboxyl groups for high adhesiveness.     

"Third drug" trial: comparative study of antihypertensive agents added to treatment when blood pressure remains uncontrolled by a beta blocker plus thiazide diuretic.

Hydralazine, labetalol, methyldopa, minoxidil, prazosin, and placebo were compared when added by random allocation to atenolol 100 mg and bendrofluazide 5 mg daily in a series of 238 hypertensive patients inadequately controlled by the beta blocker-diuretic combination. Atenolol was withdrawn in those allocated to labetalol, and minoxidil was given only to men. The order of acceptability was: placebo, hydralazine, prazosin, methyldopa, minoxidil, labetalol. Minoxidil was more effective than the other active drugs, which had similar potency to one another. All the active agents were more effective than placebo. Hydralazine was the most generally suitable third drug, with prazosin a close second. Minoxidil was especially effective in patients with less severe hypertension but the same regimen caused fluid retention in those with more severe disease. Labetalol should probably be introduced at a low dose (150 mg daily) even when replacing full doses of a previously administered beta blocker.