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PubMed2007

A longitudinal study of adolescents with perinatally or transfusion acquired HIV infection: sexual knowledge, risk reduction self-efficacy and sexual behavior.

As HIV-positive children are surviving to adolescence and beyond, understanding their HIV knowledge and sexual behavior is critical. Forty HIV+ adolescents/young adults were interviewed twice, approximately 21 months apart (mean age 16.6 and 18.3 years, respectively). Data on demographics, safer sex knowledge, sexual risk behaviors, risk reduction self-efficacy, and Tanner stage were collected. Twenty-eight percent of HIV+ youth at Time 1 and 41% at Time 2 reported being sexually active. HIV transmission/safer sex knowledge was low, increased with age, and both self-efficacy for and actual condom use was relatively high. Secondary prevention messages should be incorporated into routine medical settings.

Adolescent↗
PubMed2003

Male Japanese quails with female brains do not show male sexual behaviors.

During embryonic development, gonadal steroid hormones (androgens and estrogens) are thought to organize the sexual differentiation of the brain in the heterogametic sexes of higher vertebrates (males in mammals, females in birds). Brain differentiation of the homogametic sexes is thought to proceed by default, not requiring sex hormones for sex-specific organization. In gallinaceous birds such as the Japanese quail, female brain organization is thought to develop via estrogen-dependent demasculinization of a default male brain phenotype. We performed male donor-to-female host (MF), female-to-male (FM), male-to-male (MM), and female-to-female (FF) isotopic, isochronic transplantation of the forebrain primordium in Japanese quail embryos before gonadal differentiation had occurred; brain chimeras had a forebrain (including the hypothalamus) originating exclusively from donor cells. MM, FF, and MF chimeras all showed sexual behavior governed by the genetic sex of the host. In contrast, FM chimeras (genetically female forebrain, all other tissues genetically male) showed no mounting and only rudimentary crowing behavior. Although MM, FF, MF, and FM chimeras all showed host-typical production of steroid hormones during embryonic life, only FM chimeras were hypogonadal, had atypical low levels of circulating testosterone in adulthood, and showed reduction (crowing) or absence (mounting) of reproductive behaviors. Morphological features of the medial preoptic nucleus (a sexually dimorphic brain area) also were not male-like in FM males. These data demonstrate a brain-intrinsic, genetically determined component that organizes the sex-typical production of gonadal hormones in adulthood and call for a reevaluation of the mechanisms underlying brain sexual differentiation in other higher-vertebrate species.

Animals↗
PubMed2004

Evidence that the effect of melanocortins on female sexual behavior in preoptic area is mediated by the MC3 receptor; Participation of nitric oxide.

alpha-MSH is involved in reproductive processes and can regulate the expression of lordosis, an important component of female reproductive behavior in rats and many other species. In this study, we investigated the effects of MSH peptides on lordosis behavior when injected in medial preoptic area (POA) of ovariectomised rats primed with estradiol. The results show an increase in lordotic activity after bilateral administration of alpha-MSH and gamma-MSH. Interestingly, the treatment with the MC4 receptor antagonist HS014 did not block the stimulatory effect of alpha-MSH. Moreover, the injection of HS014 did not itself modify the lordosis quotient. Nitric oxide has been suggested to play a crucial role in the regulation of lordosis behavior via stimulation of guanylyl cyclase to synthesize cGMP. In order to determine the participation of NO in the effect of the melanocortins, another group of rats were treated with L-NAME, an inhibitor of NOS, alone or 15 min before the injection of alpha-MSH or gamma-MSH. The injection of L-NAME into the POA of E-primed rats 15 min before the test for sexual receptivity did not modify significantly the lordosis quotient at the two doses examined. The treatment with L-NAME at the lowest dose completely abolished the stimulatory effect of alpha-MSH and gamma-MSH on sexual behavior. The results indicate that the effects of MSH peptides on female sexual behavior in this area are mediated through specific MC receptor, that could be the MC3 receptor and that NO mediates the melanocortins effects.

Animals↗
PubMed1984

Sexual behavior and serum hormone levels in aging rhesus males: effects of environmental change.

Old (N = 9) and middle-aged (N = 9) rhesus males (Macaca mulatta) that were housed in the same type of home cage and the same room for several years were moved to a new location in an adjacent building. Their sexual behavior and hormone levels in the weeks preceding the move were compared to those after the move. The hypothesis that the nonspecific sensory stimulation provided by the move would increase levels of sexual behavior was not supported by the data. To the contrary, the percentages of tests with contacts, mounts, and penile erections, and the rate of contacting the female, decreased significantly for both old and middle-aged males. The intromission rate of middle-aged, but not of old, males also decreased. In consonance with previous findings, middle-aged males displayed significantly higher levels of sexual activity than did old males. The differences were observed both before and after the move. Serum testosterone levels did not differ between middle-aged and old males, and the move did not produce significant changes in testosterone levels. Serum cortisol levels were significantly higher immediately after the move (1 hr) but returned to premove levels the following day.

Aging↗
PubMed1991

Hormonal control of proceptive and receptive sexual behavior and the preovulatory LH surge in the ewe: reassessment of the respective roles of estradiol, testosterone, and progesterone.

When estrous behavior is induced in ovariectomized ewes by subjecting them to progestagen priming followed by a dose of estrogen large enough to guarantee estrus in all animals, an abnormally long period of estrus in induced, suggesting that the regime of steroid replacement needs modification. Using quantitative tests for proceptivity and receptivity, we studied the patterns of sexual behavior of intact ewes and then attempted to reproduce them in the same animals after they had been ovariectomized. We used various combinations of exogenous estrogen, androgen, and progestagen and compared the behavioral responses with an endocrine response, the preovulatory surge of luteinizing hormone (LH). In intact ewes, sexual behavior and the LH surge were closely synchronized and their characteristics differed slightly between the middle and the end of the breeding season. Proceptive behavior was not greatly affected by the frequency of tests, but the duration of receptivity was significantly reduced by frequent testing. In ovariectomized ewes, we found that: (a) progesterone priming is essential for normal patterns of receptive and proceptive behavior, and for synchronizing the behavioral and endocrine responses to estrogen; (b) androgens do not play a major role in the control of either receptive or proceptive behavior; and (c) the inclusion of a low dose of estrogen with the progestagen in the 'priming' regime improves the responses to estradiol-17 beta. Under these conditions, the timing, intensity and duration of the behavior are very close to those observed in the same ewes when they were intact and cycling spontaneously.

Animals↗
PubMed1975

Hippocampal and cortical activity during sexual behavior in the female rat.

Hippocampal and cortical activity were studied during sexual behavior in the female rat. Hippocampal theta appeared during her soliciting behavior. High-frequency theta accompanying the male's pursuit slowed when the male mounted the female and then increased in frequency during the brief continuation of lordosis following mounts without vaginal penetration. During prolonged lordosis after intromissions and ejaculations, slow theta continued. No changes in cortical frequencies were observed during mounts, intromissions, or ejaculations. During immobility (standing, sitting, and lying down) hippocampal activity became slow and irregular. High-amplitude hippocampal and, eventually, cortical spindles developed during immobility as sexual exhaustion was approached. Immobility and its accompanying electroencephalographic spindling are interpreted as indicative of a sexual satiety or inhibitory process.

Animals↗
PubMed1973

Sexual behavior in rhesus monkeys after vasectomy.

Vasectomy had no statistically significant effect on the sexual behavior of vigorous adult rhesus monkeys. Of two groups of males matched for level of sexual performance, one was vasectomized and the other underwent sham vasectomy. In sex tests administered within the month after surgery, the groups showed no difference (P .05) in rate of mounting, intromission, or ejaculation, or in any other measure of sexual or sex-related behaviors.

Aggression↗
PubMed1984

Sexual behavior correlates with the diurnal plasma testosterone range in intact male rhesus monkeys.

There is evidence that androgens are necessary for the full expression of sexual behavior in male primates, but it has proved difficult to relate sexual activity to circulating androgens levels in comparisons between intact males. In the present study, 4423 behavior tests of 32 pairs of rhesus monkeys were conducted in a constant photoperiod over a 2-year period, and there was no significant relationship between the frequency of ejaculation and plasma testosterone levels in samples collected at 0800, 1600 or 2200 h. However, the magnitude of the diurnal range between the lowest and highest levels correlated negatively with sexual behavior. As the seasonal increase in sexual activity occurred, there was a corresponding decrease in the diurnal range of plasma testosterone. Furthermore, those males with the highest numbers of ejaculations showed the smallest diurnal plasma testosterone ranges. An additional experiment with 32 males revealed that neither behavior testing nor the occurrence of ejaculation influenced the diurnal testosterone range. Consequently, we have concluded that if any causality operated it would be in the direction of a hormonal influence on behavior. These findings suggest that increased nocturnal levels of testosterone do not enhance behavior and that a threshold level maintained throughout the 24 h may be a critical endocrine factor.

Animals↗
PubMed2001

Stimulation of the medial amygdala enhances medial preoptic dopamine release: implications for male rat sexual behavior.

Increased dopamine (DA) in the medial preoptic area (MPOA) facilitates male sexual behavior. A major source of innervation to the MPOA is the medial amygdala (MeA). We now report that chemical stimulation of the MeA enhanced levels of extracellular MPOA DA in anesthetized male rats. These results suggest that DA activity in the MPOA can be regulated by input from the MeA to the MPOA.

Amygdala↗
PubMed1993

Cognitive, psychosocial, and reported sexual behavior differences between pregnant and nonpregnant adolescents.

A wide variety of variables have been related to the occurrence of adolescent pregnancy. However, many previous studies have produced conflicting results and are univariate in nature. The purpose of this study was to assess differences in pregnant and nonpregnant adolescents on variables from three domains: cognitive, psychosocial, and reported sexual behavior. Sixty-nine pregnant adolescents and 58 comparison adolescents filled out nine questionnaires presented on microcomputers. Significant differences were found on 10 of 24 univariate tests. The strongest differences concerned areas of scholastic functioning and reported sexual behavior; pregnant teenagers were more likely than nonpregnant peers to be doing poorly in school and less likely to use contraceptives. In addition, pregnant teenagers were more likely to have a relative or friend who was an adolescent mother and to expect child rearing to be easier than did the nonpregnant adolescents. A discriminant analysis was computed which correctly classified 83% of the sample, based on variables from each of the three domains. This study has served to replicate, refute, and expand on previous findings concerning the antecedents of teenage pregnancy. More importantly, this study has empirically demonstrated the multivariate and interrelated nature of variables associated with teenage pregnancy.

Adolescent↗
PubMed1992

Demographics of adolescent sexual behavior, contraception, pregnancy, and STDs.

The demographics of fertility-related behavior of youth ages 10-18 are reviewed. Data were collected from U.S. vital statistics, and birth rates, contraceptive use, sexual behavior, number and types of sexual partners, patterns of sexual initiation and sexual intercourse, and sexually transmitted diseases were examined. Despite data limitations, the demographic profile of adolescent sexual intercourse is striking. Age clearly is the single most important predictor of sexual debut.

Adolescent↗
PubMed1998

Self-reported honesty among middle and high school students responding to a sexual behavior questionnaire.

PURPOSE: To determine self-reported honesty in completing a sexual and other risk behavior questionnaire among middle and high school students, and to relate honesty scores to sexual behavior item responses as a method to detect bias in reporting. METHODS: A self-administered questionnaire measuring overall honesty (7-point rating scale), sexual honesty (5-category scale), and selected sex behaviors was used. Urban, predominantly minority middle and high schools (Grades 7-12) were examined, and participants were 3144 male and female students in middle (mean age = 13.7 +/- 2.0) and high (17.3 +/- 1.6) school health classes. RESULTS: The majority of students stated that they had been very or completely honest in responding to items on the questionnaire. Seventy-eight percent of middle school males (lowest rate), and 94% of high school females (highest rate) reported honesty. Middle school males were most likely to declare dishonesty regarding sexual behavior items, overstating their actual behavior (14%), while middle school girls were most likely to understate (8%) their behavior. Self-reported sexual honesty and reports of behavior were most consistent for understaters. That is, those subjects who answered that their questionnaire responses underreported their true sexual behavior did, in fact, report lower sexual activity on selected survey items. CONCLUSION: Middle and late adolescents reported high levels of honesty in responding to a sexuality-related questionnaire. When interpreting such questionnaire data, correction for the tendency to overstate among middle school males and understate among middle school females should be considered; conclusions about self-reports of sexual behavior among young adolescents need to take into account degree of honesty. However, the presence of some overreported and some underreported behavior does not invalidate interpretation of the overall survey findings.

Adolescent↗
PubMed1986

Stimulus qualities of a preferred female partner and sexual behavior of old rhesus males.

A vaginal lavage from a preferred female sexual partner (donor) with whom old (21-27 yr) rhesus males readily copulated or a distilled water lavage was applied to the perineum of non-preferred females (N = 8) with whom old males rarely copulated. The donor and recipients were ovariectomized and were treated with estradiol benzoate (EB) before being tested. Sexual performance of the males did not differ under the two conditions of testing, but the rate of sexual solicitation by the females was significantly higher when treated with the vaginal lavage. One month later the non-preferred females were again treated with EB and paired with the old males. In these tests the preferred female was present in a cage adjacent to and in view of the test pairs. Sexual behavior was not altered significantly, but whereas these males had never threatened or aggressed their partners in previous tests, there was a significant increase in the rate at which they threatened their partners and aggression occurred for the first time. When paired with the preferred female, males ejaculated in 100% of the tests and the average ejaculation latency was less than 2.5 minutes.

Aging↗
PubMed2004

The emotional brain: neural correlates of cat sexual behavior and human male ejaculation.

The organization of virtually all basic survival mechanisms in the central nervous system (CNS) is within the most central regions of the mesencephalon and the rostrally adjoining diencephalon; in particular, the mesencephalic periaqueductal gray (PAG) and hypothalamus. The PAG sends specific pathways to the caudal brainstem where neurons are located that, in turn, control nociception, blood pressure, heart rate, and micturition. Via projections to the nucleus retroambiguus (NRA) in the most caudal part of the medulla, the PAG controls the intra-abdominal pressure associated with vocalization, vomiting, and parturition. In cats, the PAG also controls sexual posture via NRA projections to motoneurons in the lumbosacral cord. These NRA-lumbosacral motoneuronal pathways are almost nine times stronger in the estrous vs. non-estrous female cat. While neuronal activity in specific CNS pathways is now known to control sexual behavior in the cat, how is it organized in the human? PET-scan results on human ejaculation have revealed that the meso-diencephalic transition zone is particularly and strongly activated. This region includes the so-called ventral tegmental area that is also known as a "reward area." For example, it is also activated during a heroin rush. Other strongly activated structures during sexual activity include the cerebellum and lateral part of the corpus striatum. At the level of the cerebral cortex, areas in the prefrontal and parietal cortex are also activated, but exclusively on the right side. Further study of these structures should certainly lead to better insight into human sexual behavior and provide the possibility to improve sexual activity in those who suffer from problems in this area.

Animals↗
PubMed1994

Women's protective sexual behaviors: a test of the health belief model.

Heterosexual transmission of the human immunodeficiency virus (HIV) has become a significant health issue for women. The present study describes the extent to which a sample of women from an urban area report making efforts to protect themselves from becoming infected with HIV through several protective sexual behaviors. Secondly, we assess the extent to which adoption of these protective behaviors can be explained by health beliefs and previous HIV testing. Forty-nine percent of the sample reported having used a condom in the past year because of fear of AIDS and 48% reported having carried condoms. Women in this sample perceived themselves to be moderately susceptible to AIDS and they were well aware of the severity of the disease. Women tended to think that protecting themselves from AIDS would not be overly burdensome and that the recommended sexual protective behaviors were highly effective for preventing AIDS. Messages about the severity of AIDS and the effectiveness of protective sexual behaviors seem to be reaching women. Beliefs about personal susceptibility were consistently associated with the adoption of multiple protective behaviors, suggesting that messages emphasizing the ubiquity of risk, especially in demographically high-risk populations, may be particularly appropriate and effective.

Adult↗
PubMed1989

Neuropeptides and male sexual behavior.

Evidence is rapidly accumulating that a number of neuropeptides are involved in the central control of male sexual behavior. This is consistent with their neuroanatomical distribution, i.e., in CNS loci previously implicated in the control of this behavior such as the medial preoptic area, and with recent findings that the peptide content of some of these regions is regulated by testosterone or its metabolites. Most of the work has been done using rats, but relevant human studies have been included whenever such material has been available. At this point there are relatively few studies which directly demonstrate the involvement of peptides in this behavior. Inhibitory and facilitatory actions, however, have been demonstrated following injections of peptides, peptide antisera, or antagonists into the CNS of male rats. Significant new developments include demonstrations that injections of substance P and A-MSH directly into the medial preoptic area can facilitate this behavior, while ventricular injection of an oxytocin antagonist can produce a powerful inhibition. The emerging picture is that GnRH, oxytocin, A-MSH and substance P stimulate, while CRF, beta-endorphin, prolactin, and neuropeptide Y are inhibitory. The inhibitory peptides CRF, beta-endorphin and prolactin are related, as they are released in response to stress. This may be relevant to the low level of sexual motivation in some depressed men. Questions concerning sites of action and mechanisms of action which mediate the behavioral effects which have been demonstrated remain largely unanswered.

Animals↗
PubMed1994

Changes in monoamine turnover in forebrain areas associated with masculine sexual behavior: a microdialysis study.

This report compares the changes in the main dopamine (DA) and serotonin (5-HT) metabolites, respectively dihydroxyphenylacetic acid (DOPAC) and 5-hydroxy indoleacetic acid (5-HIAA) in three relatively close brain regions, namely the nucleus accumbens (ACB), the medial preoptic area, and the medial basal hypothalamus (MBH), as well as DA in the ACB, of copulating male rats. All these neurochemicals remained fairly stable when the animals were exposed to non sexual social stimuli (castrated females), and they increased during mating with receptive females. There were regional differences in these copulation-related changes, however, with those in the MBH being shorter-lived. There were also differences in the time-course of the changes in DOPAC and 5-HIAA the latter being slower. It is suggested that they reflect the involvement of the DA and 5-HT innervation of diencephalic structures in, respectively the appetitive and consummatory/satiation mechanisms of sexual behavior. The physiological relevance of these neurochemical changes is supported by the lack of differences between the standard measures for sexual behavior recorded before surgery and during the dialysis session.

3,4-Dihydroxyphenylacetic Acid↗