Potential pathogenic mechanisms of periodontitis associated pregnancy complications

The authors investigated the behavioral actions of vasotocin (VT) in castrated testosterone-treated male Japanese quail. The appetitive and consummatory components of sexual behavior as well as the occurrence frequency of crows were inhibited, in a dose-dependent manner, by injections of VT. The authors observed opposite effects after injection of the V1 receptor antagonist, dPTyr(Me)AVP. Lower doses of VT were more active after central than after systemic injection, and effects of systemic injections of VT were blocked by a central injection of dPTyr(Me)AVP. The behavioral inhibition was associated with a modified diuresis after systemic but not central injection. These results provide direct evidence that VT affects male sexual behavior in quail by a direct action on the brain independent of its peripheral action on diuresis.     

Role of septal vasopressin innervation in paternal behavior in prairie voles (Microtus ochrogaster)

After being paired with females, male prairie voles show major changes in their social behaviors among which is an increase in paternal responsiveness. These changes are accompanied by fluctuations in the density of the [Arg8]vasopressin-immunoreactive (AVP-ir) fibers in the lateral septum, suggesting that septal AVP might be involved in these changes. To explore a possible involvement of septal AVP in paternal responsiveness, we tested whether injections of saline, AVP, or the V1a receptor antagonist [1-(beta-mercapto-beta, beta-cyclopentamethylenepropionic acid),2-(O-methyltyrosine]AVP [d(CH2)5Tyr(Me)AVP] into the lateral septum influenced the four most prominent paternal activities displayed by male prairie voles; grooming, crouching over, contacting, and retrieving pups. In a first experiment, sexually inexperienced males received a single injection of AVP, saline, or d(CH2)5Tyr(Me)AVP in the lateral septum, after which their paternal responsiveness was recorded during a 10-min period. AVP-injected animals spent more time contacting and crouching over pups, while d(CH2)5Tyr(Me)AVP-injected animals spent less time grooming pups than saline-injected animals. In a follow-up study, one group of animals received an injection of AVP preceded by an injection of saline or d(CH2)5Tyr(Me)-AVP into the lateral septum. A second group of animals received an injection of saline preceded by an injection of saline or d(CH2)5Tyr(Me)AVP into the lateral septum. In both groups, animals spent less time grooming, crouching over, and contacting pups if they had first been injected with d(CH2)5Tyr(Me)AVP. Control experiments suggested that the effects of AVP on paternal responsiveness were dose- and site-specific. These data suggest that septal AVP enhances paternal responsiveness by a V1a receptor-mediated mechanism.     

Effects of neurochemical lesions of the preoptic area on male sexual behavior in the Japanese quail

Two experiments were carried out during which the noradrenergic neurotoxin, 5-amino-2,4-dihydroxy-alpha-methylphenylethylamine (5-ADMP) was applied to the brain of quail in order to evaluate the role of the noradrenergic system in the control of male copulatory behavior. In the first experiment, the ICV injection of 5-ADMP slightly enhanced the sexual behavior observed in testosterone (T)-treated castrated male quail. This brings additional support to the notion that norepinephrine tonically inhibits male copulatory behavior in quail. In the second experiment, 5-ADMP implanted directly into the preoptic area disrupted the restoration by T of copulatory behavior in castrated quail and, at the same time, produced a brain lesion that partly destroyed the sexually dimorphic medial preoptic nucleus, a previously established site of T action on behavior. These lesions produced by a high (presumably too high) concentration of neurotoxin provided an independent confirmation of effects previously observed after electrolytic lesions. Correlation analyses also confirmed that the medial part of the POM just rostral to the anterior commissure is more closely associated with copulatory behavior and may, therefore, represent a key center for steroid action on this behavior.     

Differences in the sexual conditioned behavior of male and female Japanese quail (Coturnix japonica).

The conditioned responses of male and female Japanese quail (Coturnix japonica) were compared in a Pavlovian conditioning procedure in which presentation of a brief conditioned stimulus was immediately followed by the release of a copulation partner. Male quail vigorously approached the conditioned stimulus and were much more likely to enter the compartment housing their copulation partner than were female birds (Experiment 1). In females, sexual conditioning resulted in increased squatting (Experiment 2). This response was the reflection of sexual behavior rather than more general social behavior (Experiment 3). These findings provide the first definitive evidence of sexual learning in female quail and are consistent with the interpretation that sexual conditioning increases sexual arousal or receptivity in both sexes but the increase has different behavioral manifestations in male and female quail. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aromatase inhibition blocks the activation and sexual differentiation of appetitive male sexual behavior in Japanese quail

Two experiments investigated the role of estrogens in the activation and sexual differentiation of appetitive sexual behavior (ASB) in Japanese quail (Coturnix japonica) as measured by a learned social proximity response. Injection of the aromatase inhibitor R767 13 in castrated, testosterone (T)-treated male quail completely suppressed ASB, confirming that, like consummatory sexual behavior, ASB is mediated by T aromatization. ASB is not observed in female quail, even if they are treated with T as adults. The role of embryonic estrogens in the sexual differentiation of ASB was tested by blocking estrogen synthesis in ovo. Control male and T-treated female quail deprived of estrogens during embryonic life learned the social proximity response used to assess ASB, whereas control female quail did not, despite the presence of high T. Thus, ASB is demasculinized by the action of embryonic estrogens during ontogeny as is consummatory behavior.     

Is sexual motivational state linked to dopamine release in the medial preoptic area?

The medial preoptic area (mPOA) is a key site for the dopaminergic enhancement of male sexual behavior. Dopamine release increases in the rat mPOA with mating, supporting the critical stimulatory role played by preoptic dopamine on male sexual behavior. However, it has been questioned whether dopamine is specifically related to the occurrence of male sexual behavior and not simply involved in general arousal. To address this question, we asked whether dopamine release in the mPOA is linked to the production of male sexual behavior in Japanese quail (Coturnix japonica), a species that exhibits a much shorter temporal pattern of copulation than rats and does not have an intromittent organ, resulting in a very different topography of their sexual response. Extracellular samples from the mPOA of adult sexually experienced male quail were collected every 6 min before, during, and after exposure to a female using in vivo microdialysis and analyzed using high-performance liquid chromatography with electrochemical detection. Extracellular dopamine significantly increased in the presence of a female and returned to baseline after removal of the female. However, quail that failed to copulate did not display this increased release. These findings indicate that it is not solely the presence of a female that drives dopamine release in males, but how a male responds to her. Furthermore, in quail that copulated, dopamine release did not change in samples collected during periods of no copulation. Together, these findings support the hypothesis that dopamine action in the mPOA is specifically linked to sexual motivation and not only to copulatory behavior or physical arousal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous vasopressin does not mediate hypoxia-induced anapyrexia in rats

The present study was designed to test the hypothesis that arginine vasopressin (AVP) mediates hypoxia-induced anapyrexia. The rectal temperature of awake, unrestrained rats was measured before and after hypoxic hypoxia, AVP-blocker injection, or a combination of the two. Control animals received saline injections of the same volume. Basal body temperature was 36.52 +/- 0.29 degreesC. We observed a significant (P < 0.05) reduction in body temperature of 1. 45 +/- 0.33 degreesC after hypoxia (7% inspired O2), whereas systemic and central injections of AVP V1- and AVP V2-receptor blockers caused no change in body temperature. When intravenous injection of AVP blockers was combined with hypoxia, we observed a reduction in body temperature of 1.49 +/- 0.41 degreesC (V1-receptor blocker) and of 1.30 +/- 0.13 degreesC (V2-receptor blocker), similar to that obtained by application of hypoxia only. Similar results were observed when the blockers were injected intracerebroventricularly. The data indicate that endogenous AVP does not mediate hypoxia-induced anapyrexia in rats.     

Sexual fetishism in a quail (Coturnix japonica) model system: Test of reproductive success.

In the present study, the authors explored the reproductive consequences of fetishistic behavior in a previously developed animal model of sexual fetishism (F. K?ksal et al., 2004). Male domesticated quail (Coturnix japonica) received sexual conditioning trials in which a terrycloth object (the conditioned stimulus [CS]) was paired with the opportunity to copulate with a female quail (the unconditioned stimulus). Approximately half of the male quail came to copulate with the CS object and were considered to have developed fetishistic behavior. Each of the male quail was then tested with a female quail, whose eggs were incubated to determine rates of fertilization. The CS object was present for 30 s before and during the copulation test. Fetishistic male quail were slower to achieve cloacal contact with the female quail and showed less efficient copulatory behavior. However, they fertilized a greater proportion of eggs than nonfetishistic male quail. These results are unexpected from previous studies of the relationship between reproductive success and copulatory behavior and are discussed in terms of how fetishistic behavior directed toward an inanimate object may modify male-female interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intermanual differences on motor and psychomotor tests in alcoholics: no evidence for selective right-hemisphere dysfunction

The effects of pharmacological manipulations of dopaminergic transmission on appetitive and consummatory aspects of male sexual behavior were investigated in castrated male Japanese quail treated with exogenous testosterone. Appetitive male sexual behavior was assessed by measuring a learned social proximity response and consummatory behavior was assessed by measuring copulatory behavior per se. The nonselective dopamine receptor agonist, apomorphine, inhibited in a dose-dependent manner both components of male sexual behavior. Two indirect dopamine agonists were also tested. Nomifensine, a dopamine re-uptake inhibitor, decreased appetitive sexual behavior but increased the frequency of mount attempts, a measure of consummatory sexual behavior. Amfonelic acid, a compound that enhances dopaminergic tone by a complex mechanism, increased aspects of both appetitive and consummatory behaviors. These data suggest that, in quail, as in rodents, increases in dopaminergic tone facilitate both appetitive and consummatory aspects of male sexual behavior. Apomorphine may be inhibitory in quail because it acts primarily on D2-like receptors, unlike in rats, where it stimulates sexual behavior and acts primarily on D1-like receptors at low doses but interacts with D2-like receptors at higher doses. This is supported by the observation that stereotyped pecking, a behavior stimulated selectively in quail by D2 agonists, was increased by apomorphine but not by the two indirect agonists. The observed partial dissociation between the effects of these dopaminergic agonists on appetitive and consummatory sexual behaviors suggests that these two components of male sexual behavior may be controlled by the action of dopamine through different neuronal systems.     

An NMDA antagonist impairs copulation and the experience-induced enhancement of male sexual behavior in the rat.

Sexual experience facilitates subsequent male sexual behavior; activation of the N-methyl-D-aspartate (NMDA) glutamate receptor may play a role in this experience-induced enhancement. In this article, the authors report that systemic injections of MK-801, an NMDA receptor antagonist, impaired male sexual behavior in sexually naive and sexually experienced male rats. Furthermore, saline-treated rats that received 7 daily exposures to an inaccessible estrous female instead of sexual experience displayed enhancement of copulation on the following day. Injections of MK-801 before each of these exposures inhibited the experience-induced enhancement on the drug-free test on Day 8. These data suggest that stimulation of NMDA receptors enhances sexual performance immediately and mediates the experience-induced enhancement of subsequent copulatory behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine release in the medial preoptic area is related to hormonal action and sexual motivation.

To help elucidate how general the role of dopamine (DA) release in the medial preoptic area (mPOA) is for the activation of male sexual behavior in vertebrates, we recently developed an in vivo microdialysis procedure in the mPOA of Japanese quail. Using these techniques in the present experiment, the temporal pattern of DA release in relation to the precopulatory exposure to a female and to the expression of both appetitive and consummatory aspects of male sexual behavior was investigated. Extracellular samples from the mPOA of adult sexually experienced male quail were collected every 6 min before, while viewing, while in physical contact with, and after exposure to a female. In the absence of a precopulatory rise in DA, males failed to copulate when the barrier separating them from the female was removed. In contrast, males that showed a substantial increase in mPOA DA during precopulatory interactions behind the barrier, copulated with females after its removal. However, there was no difference in DA during periods when the quail were copulating as compared to when the female was present but the males were not copulating. In addition, we show that precopulatory DA predicts future DA levels and copulatory behavior frequency. Furthermore, the size of the cloacal gland, an accurate indicator of testosterone action, is positively correlated with precopulatory DA. Taken together, these results provide further support for the hypothesis that DA action in the mPOA is specifically linked to sexual motivation as compared to copulatory behavior per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual dimorphism in the social proximity behavior of Japanese quail (Coturnix coturnix japonica).

Previous research by the present authors (see record 1986-16367-001) showed that after opportunity for copulation, male Japanese quail spent about 75% of their time throughout daylight hours near a window that provided visual access to a female conspecific. In Exp I of the present study, 8 female Japanese quail typically spent less than 20% of their time near a window that provided visual access to 1 of 8 male conspecifics under comparable conditions. In Exp II, using the same Ss, a small clear plastic cage was placed in a large test arena, and Ss were observed when the cage was either empty or contained a sexual partner. Males tended to remain much closer to the cage when it contained a female conspecific than when it was empty. In contrast, the presence of a male did not significantly attract females to the cage area. These findings demonstrate strong sexual dimorphism in the social proximity behavior of Japanese quail. Results are discussed in terms of implications concerning the social structure of Japanese quail and implications for studies of sexual classical conditioning. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photoperiodic and endocrine control of social proximity behavior in male Japanese quail (Coturnix coturnix japonica).

Experiment 1 demonstrated that the social proximity behavior of male Japanese quail declines significantly when photostimulation is restricted to 2 hr daily, but can be restored by reinstituting the normal schedule. Changes in the photoperiod produced corresponding changes in the size of the cloacal gland, an androgen-dependent organ. The low levels of social proximity behavior and cloacal gland size of males maintained on short daily exposures to light also could be reversed by sc implants of testosterone (Experiment 2), and this recovery was to some extent sensitive to testosterone dose (Experiment 3). The present studies indicate that social proximity behavior in male Japanese quail is androgen dependent and provide a behavioral assay for neurohormonal studies of sexual behavior that does not depend on brief phasic responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of the effects of 17 α–methyltestosterone, methandrostenolone, and nandrolone decanoate on the sexual behavior of castrated male rats.

In a series of 3 experiments, adult male Long-Evans rats were castrated and treated with 1 of 3 different anabolic-androgenic steroid (AAS) compounds ( 17 α-methyltestosterone, methandrostenolone, or nandrolone decanoate) for 6 weeks. In each experiment, subjects received daily injections of a high, medium, or low dose of AAS or the oil vehicle. The AAS effects on body weight in gonadectomized male rats were modest, and no effects on locomotor activity were observed. The AAS compounds administered at doses comparable with human abuse levels were not equipotent in maintaining male sexual behavior patterns (nandrolone decanoate > methandrostenolone > 17 α-methyltestosterone). In addition, the behavioral actions of AAS compounds did not parallel stimulation of sexual accessory glands. The authors reported that this study is the first to quantify the dose–response characteristics of individual AAS compounds with regard to these behavioral and endocrine measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of beta-endorphin and Met- and Leu-enkephalin on steroid hormone-induced lordosis in ovariectomized female rats

The effect of intrathirdventricular (I.T.V.) injections of beta-endorphin, anti-beta-endorphin antiserum, Met-enkephalin, Leu-enkephalin, and naloxone on the initial activation and final development of steroid hormone-mediated induction of female sexual receptivity was studied in ovariectomized female rats. The lordosis response to male mounts in ovariectomized rats after subcutaneous (S.C.) estradiol benzoate (EB) and progesterone (Prog) priming was facilitated by beta-endorphin, and Met-enkephalin (10 microg x 5 microl(-1)), but inhibited by Leu-enkephalin, when the peptides were injected into the third ventricle at the time of S.C. EB priming. A lower dose Met-enkephalin had no effects. Lordosis behavior in steroid hormone-primed rats was significantly facilitated when I.T.V. injections of Met-enkephalin were given 1 h prior to behavioral testing (47 h after EB priming). At 1 h prior to behavioral testing (47 h after EB priming), I.T.V. injection of beta-endorphin significantly inhibited lordosis behavior, especially at the higher dose of beta-endorphin (10 microg x 5 microl(-1)). Under those conditions, Leu-enkephalin had no effect. Lordosis behavior of ovariectomized female rats receiving S.C. steroid hormones and I.T.V. injection of anti-beta-endorphin antiserum was significantly inhibited when anti-beta-endorphin antiserum was injected at the time of EB priming. However, lordosis was significantly facilitated when anti-beta-endorphin antiserum was injected 1 h prior to the behavior testing (47 h after EB priming). In contrast, I.T.V. injection of the opioid antagonist naloxone given either at the time of EB priming or 1 h prior to behavioral testing (47 h after EB priming) decreased lordosis behavior. The present results suggest that 1) beta-endorphin, Met-enkephalin, and Leu-enkephalin have differential effects in the control of lordosis behavior; 2) the opioidergic systems may modulate initial-stage and final-stage estrogen-induced lordosis behavior; and 3) the opioidergic systems could be divided into the endorphinergic modulation-type and enkephalinergic modulation-type, based on their effects on lordosis behavior.     

A comparative approach to the study of dopamine and male sexual behavior: What can Japanese quail teach us? A reply to Pfaus (2010).

One of the most robust findings about dopamine (DA) is that the stimulation of dopaminergic systems promotes the activation of male sexual behavior. The commentary by Pfaus (see record 2010-24688-009) included a thorough review of studies of DA and male sexual behavior. We agree with him that the release of DA in the preoptic region in male quail in response to females and in association with the exhibition of male sexual behavior appears to be highly conserved and that it seems to have evolved very early in the evolutionary history of the vertebrate brain. However, additional data have been collected indicating that there may be significant species differences in the dopaminergic regulation of male behavior in quail compared with rats. In this response, we take the opportunity to make a few broader points about DA and male sexual behavior in light of other studies that have been conducted in birds and introduce some interesting taxonomic variation that is still not well understood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex versus sweet: Opposite effects of opioid drugs on the reward of sucrose and sexual pheromones.

Endogenous opioids mediate some reward processes involving both natural (food, sweet taste) and artificial (morphine, heroin) rewards. In contrast, sexual behavior (which is also reinforcing) is generally inhibited by opioids. To establish the role of endogenous opioids for a newly described natural reinforcer, namely male sexual pheromones for female mice, we checked the effects of systemic injections of the general opioid antagonist naloxone (1-10 mg/kg) and the agonist fentanyl (0.1- 0.5 mg/kg) in a number of behavioral tests. Naloxone affected neither the innate preference for male-soiled bedding (vs. female-soiled bedding) in 2-choice tests nor the induction of place conditioning using male pheromones as rewarding stimuli, although it effectively blocked the preference for consuming a sucrose solution. In contrast, fentanyl inhibited the preference for male chemosignals without altering sucrose preference. These results suggest that, in macrosmatic animals such as rodents, opioidergic inhibition of sexual behavior might be due, at least partially, to an impaired processing of pheromonal cues and that the hedonic value of sweet-tasting solutions and sexual pheromones are under different opioid modulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormonal control of behavior in the Japanese quail.

Adult male and female Japanese quail were functionally castrated by exposure to a short photoperiod and then injected with either estradiole benzoate (EB) or testosterone propionate (TP). Females injected with EB (n = 24) exhibited normal sexual receptivity again but displayed no male courtship behavior. Males injected with EB (n = 10) showed both male and female copulatory patterns. Females injected with TP (n = 14) showed little sexual behavior of any sort, while males injected with TP (n = 10) displayed male sexual behavior. The male quail is thus more bisexual than the female. In contrast with mammalian species, the female is more bisexual. The difference is discussed in relation to the differences in the embryology and cytogenetics of birds and mammals. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine: Helping males copulate for at least 200 million years: Theoretical comment on Kleitz-Nelson et al. (2010).

Brain dopamine (DA) systems are implicated in a variety of behavioral responses and clinical syndromes, including sex, drug addiction, feeding, satiety, sleep, wakefulness, arousal, attention, reward, decision-making, depression, anxiety, psychosis, and movement disorders. The paper in this issue (see record 2010-24688-004) by Kleitz-Nelson, Dominguez, and Ball (2010) shows how DA release in the medial preoptic area of male quail are activated in an androgen-dependent manner during appetitive and consummatory phases of sexual behavior, similar to that reported previously in male rats. Those data suggest that the steroid-dependent role of hypothalamic DA in male sexual behavior has been conserved through evolutionary time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fosinoprilate prolongs the action potential: reduction of iK and enhancement of the L-type calcium current in guinea pig ventricular myocytes

Changes in the gross and cellular morphology of the nucleus preopticus medianus (POMn) were measured in response to changes in photoperiod in adult male Japanese quail (Coturnix japonica). POMn volume and the soma size of a dorsolateral population of neurons within POMn decreased when birds were moved from long day housing conditions (16L,8D) to short day housing conditions (8L,16D), and then increased again when birds were moved back to long day conditions, presumably as a function of the changes in circulating testosterone that accompanied changing daylengths. Male Japanese quail exhibit sexual behavior only when housed under long day housing conditions that approximate the photoperiod of the spring/summer breeding season, and do not exhibit sexual behavior when housed under short day conditions characteristic of fall/winter. Because POMn is known to be critically involved in the expression of male copulatory behavior, these morphological changes in the adult brain likely represent key functional events associated with the seasonal regulation of sexual behavior in male Japanese quail.