Deissy Herrera-Covarrubias

Conditioned same-sex partner preference in male rats is facilitated by oxytocin and dopamine: Effect on sexually dimorphic brain nuclei

Conditioned same-sex partner preference can develop in male rats that undergo cohabitation under the effects of quinpirole (QNP, D2 agonist). Herein, we assessed the development of conditioned same-sex social/sexual preference in males that received either nothing, saline, QNP, oxytocin (OT), or QNP+OT during cohabitation with another male (+) or single-caged (-). This resulted in the following groups: (1) Intact-, (2) Saline+, (3) QNP-, (4) OT-, (5) QNP+, (6) OT+ and (7) QNP/OT+. Cohabitation occurred during 24h in a clean cage with a male partner that bore almond scent on the back as conditioned stimulus. This was repeated every 4 days for a total of three trials. Social and sexual preference were assessed four days after the last conditioning trial in a drug-free test in which experimental males chose between the scented familiar male and a novel sexually receptive female. Results showed that males from groups Intact-, Saline+, QNP- and OT- displayed a clear preference for the female (opposite-sex), whereas groups QNP+, OT+ and QNP/OT+ displayed socio/sexual preference for the male partner (same-sex). In Experiment 2, the brains were processed for Nissl dye and the area size of two sexually dimorphic nuclei (SDN-POA and SON) was compared between groups. Males from groups OT-, OT+ and QNP/OT+ expressed a smaller SDN-POA and groups QNP+ and QNP/OT+ expressed a larger SON. Accordingly, conditioned same-sex social/sexual partner preference can develop during cohabitation under enhanced D2 or OT activity but such preference does not depend on the area size of those sexually dimorphic nuclei.

The role of orgasm in the development and shaping of partner preferences

Background The effect of orgasm on the development and shaping of partner preferences may involve a catalysis of the neurochemical mechanisms of bonding. Therefore, understanding such process is relevant for neuroscience and psychology. Methods A systematic review was carried out using the terms Orgasm, Sexual Reward, Partner Preference, Pair Bonding, Brain, Learning, Sex, Copulation. Results In humans, concentrations of arousing neurotransmitters and potential bonding neurotransmitters increase during orgasm in the cerebrospinal fluid and the bloodstream. Similarly, studies in animals indicate that those neurotransmitters (noradrenaline, oxytocin, prolactin) and others (e.g. dopamine, opioids, serotonin) modulate the appetitive and consummatory phases of sexual behavior and reward. This suggests a link between the experience of orgasm/sexual reward and the neurochemical mechanisms of pair bonding. Orgasm/reward functions as an unconditioned stimulus (UCS). Some areas in the nervous system function as UCS-detection centers, which become activated during orgasm. Partner-related cues function as conditioned stimuli (CS) and are processed in CS-detector centers. Conclusions Throughout the article, we discuss how UCS- and CS-detection centers must interact to facilitate memory consolidation and produce recognition and motivation during future social encounters.

Heterosexual experience prevents the development of conditioned same-sex partner preference in male rats ☆

Sexual partner preferences can be strengthened, weakened or even drastically modified via Pavlovian conditioning. For example, conditioned same-sex partner preference develops in sexually-naïve male rats that undergo same-sex cohabitation under the effects of quinpirole (QNP, D2 agonist). Here, we assessed the effect of prior heterosexual experience on the probability to develop a conditioned same-sex preference. Naïve or Sexually-experienced males received either Saline or QNP and cohabited during 24h with a male partner that bore almond scent on the back as conditioned stimulus. This was repeated every 4days for a total of three trials and resulted in four groups (Saline-naïve, Saline-experienced, QNP-naïve, QNP-experienced). Social and sexual preference were assessed four days after the last conditioning trial in a drug-free test in which experimental males chose between the scented familiar male and a novel sexually receptive female. Results showed that Saline-naïve, Saline-experienced and QNP-experienced displayed a clear preference for the female (opposite-sex). By contrast, only QNP-naïve males displayed a same-sex preference. Accordingly, QNP-experienced males were not affected by the conditioning process and continued to prefer females. We discuss the effects of copulation and D2 agonists on the facilitation and/or disruption of conditioned partner preferences.

Effect of hyperprolactinemia on PRL-receptor expression and activation of Stat and Mapk cell signaling in the prostate of long-term sexually-active rats

The abnormal elevation of serum PRL, referred to as hyperprolactinemia (HyperPRL), produces alterations in several reproductive parameters of male rats such as penile erection or decreased tendency to reach ejaculation. Additionally, this situation produces a significant modification of prostate histology, as observed in the epithelial structure and alveolar area, which could reach a level of hyperplasia in the long-term. In this tissue, HyperPRL produces an increase in expression of PRL receptors and activation of the Stat3 signaling pathway that is correlated with the evolution of prostate pathologies. However, the impact of HyperPRL in long-term sexually active male rats is unknown. In this work, using constantly copulating Wistar male rats with induced HyperPRL, we analyzed the level of serum PRL, the effect on prostate PRL receptors, and activation of pStat3, pStat5 and Mapk signaling pathways. Two procedures to induce HyperPRL were employed, comprising daily IP administration or adenohypophysis transplant, and although neither affected the execution of sexual behavior, the serum PRL profile following successive ejaculations was affected. Messenger RNA expression of the short and long isoforms of the PRL receptor at the ventral prostate was affected in different ways depending on the procedure to induce HyperPRL. The ventral prostate did not show any modification in terms of activation of the pStat5 signaling pathway in subjects with daily administration of PRL, although this was significantly increased in ADH transplanted subjects in the second and fourth consecutive ejaculation. A similar profile was found for the pStat3 pathway which additionally showed a significant increase in the third and fourth ejaculation of daily-injected subjects. The Mapk signaling pathway did not show any modifications in subjects with daily administration of PRL, but showed a significant increase in the second and third ejaculations of subjects with ADH transplants. Thus, although sexual behavior was not modified, HyperPRL modified the expression of PRL receptors and the activation of signal pathways in the prostate tissue. Hence, it is probable that prostatic alterations precede the sexual behavioral deficits observed in subjects with HyperPRL.

Understanding Sexual Partner Preference: from Biological Diversity to Psychiatric Disorders

Purpose of ReviewThe aim of this review is to provide current evidence on the biological and psychological mechanisms that underlie sexual partner preferences (SPP) in humans and animals.Recent FindingsSPP depend mainly on prenatal (adaptive) organization of the brain, but can be drastically modified via learning under enhanced dopaminergic (DA) and oxytocinergic (OT) activity.SummarySPP can be categorized as in those directed towards partners who display indicators of biological fitness (IBF) or towards partners who do not show those indicators. The IBF function as unconditioned stimuli that presumably activate prenatally organized brain areas that mediate the salience of those stimuli. However, we discuss some evidence indicating that SPP not directed towards IBF (i.e., paraphilias) might be consequence of a learning process that occurs under enhanced DA or OT activity, resulting in new powerful learning with additional brain areas involved.

Olfactory conditioned same-sex partner preference in female rats: Role of ovarian hormones

ABSTRACT The dopamine D2‐type receptor agonist quinpirole (QNP) facilitates the development of conditioned same‐sex partner preference in males during cohabitation, but not in ovariectomized (OVX) females, primed with estradiol benzoate (EB) and progesterone (P). Herein we tested the effects of QNP on OVX, EB‐only primed females. Females received a systemic injection (every four days) of either saline (Saline‐conditioned) or QNP (QNP‐conditioned) and then cohabited for 24 h with lemon‐scented stimulus females (CS +), during three trials. In test 1 (female‐female) preference was QNP‐free, and females chose between the CS + female and a novel female. In test 2 (male‐female) they chose between the CS + female and a sexually experienced male. In test 1 Saline‐conditioned females displayed more hops & darts towards the novel female, but QNP‐conditioned females displayed more sexual solicitations towards the CS + female. In test 2 Saline‐conditioned females displayed a clear preference for the male, whereas QNP‐conditioned females displayed what we considered a bisexual preference. We discuss the effect of dopamine and ovarian hormones on the development of olfactory conditioned same‐sex preference in females. HIGHLIGHTSConditioned same‐sex partner preference (CSSP) has been reported in naïve male ratsCSSP is formed during same‐sex cohabitation under enhanced D2‐type activityCSSP does not occur in ovariectomized, hormone‐primed (EB + P) femalesHerein, we induced CSSP in ovariectomized EB‐only treated femalesWe discuss the role of ovarian hormones and dopamine in the development of CSSP

Status epilepticus during early development disrupts sexual behavior in adult female rats: Recovery with sexual experience

Female sexual behavior is sensitive to stress and diseases. Some studies have shown that status epilepticus (SE) can affect sexual proceptivity and receptivity in female rats and also increases reject responses towards males. However, epidemiologic studies indicate that SE is more frequent in young individuals. Herein, we assessed the effects of SE in infant females on their sexual behavior during adulthood. Thirteen-day-old (P13) rat pups received intraperitoneal injections of lithium chloride (3 mEq/kg). Twenty hours later, at P14, SE was induced by subcutaneous injection of pilocarpine hydrochloride (100 mg/kg s.c.). Control animals were given an equal volume of saline subcutaneously. The animals were weaned at P21 and, later in adulthood, were ovariectomized and hormone-primed with estradiol+progesterone, and their sexual behavior assessed during 4 separate trials of 30 min each with a stud male. Our results indicate that proceptive behaviors (solicitations and hops and darts) were impaired during the first trial, but no alterations were observed for receptivity and attractivity. By trial 3, all SE females displayed normal proceptivity. These results indicate that SE in infancy readily affects proceptivity in a reversible manner. We discuss the role of sexual experience in recovery.

Halitosis and weight loss in a cat.

and scheduled a complete oral evaluation under general anesthesia. Five days later, the cat was brought back to the university and was anesthetized with a mixture of dexmedetomidine (40 μg per kg body weight administered intramuscularly) and ketamine and zolazepam (5 mg p er kg b ody we ig ht admini s tered intravenously). We took a blood sample to carry out a complete blood count, blood biochemistry analysis and immunoassays On clinical examination, the cat’s rectal temperature was 38.5 °C. The animal was bright, alert, responsive and easily examined, except if touched around the mouth when it would become distressed. A careful examination of the mouth showed that the gums were highly sensitive to touch and inflamed (Fig. 1). We administered an antibiotic (5 mg enrofloxacin per kg body weight, subcutaneously, once daily for 5 d), sent the cat home with its owner daily We carried out a study assessing the effects of Nepeta cataria (catnip) on cat behavior. The study was approved by the Internal Committee for the Care and Use of Laboratory Animals of the Graduate Program of Neuroethology at University of Veracruz, following the Official Mexican Standard NOM-062-ZOO-1999 (Technical Specifications for the Production, Care and Use of Laboratory Animals). In this study, pet owners brought their cats to the university, where we exposed the animals to dry commercial catnip (Whisker City, Pacific Coast Distributing, Phoenix, AZ) for 10 min and video-recorded their behavior. All the owners were familiar with the effects of catnip, and none expressed concerns about the nature of the study. Most owners fed their cats a commercial dry pellet feed only, but a few owners also gave wet (canned) cat food once a day as a reward. Five weeks into the study, we noted that a 5-y-old female cat was no longer responding to catnip and had halitosis. The owner had also noted the foul breath as well as a progressive weight loss in the cat over the past few weeks. The cat refused to eat dry food, waiting until she was given wet food to eat at night. We offered to investigate the cat’s problem, and the owner consented. A complete history obtained at the start of the study indicated that the cat was vaccinated against feline rhinotracheitis, calicivirus, panleukopenia and chlamydia (Felocell CVR-C) and rabies (Defensor 3), but not against feline leukemia. Although the owner had indicated the cat was always kept indoors, he told us that 4 months previously, the cat had escaped and was lost for several days in the neighborhood, where feral cats roamed. Halitosis and weight loss in a cat Genaro A. Coria-Avila, DVM, MSc, PhD1, José L. González-Hernández, DVM2, Juan B. Rosales-Raya, MVZ, Esp LCV3, María Luisa Aguirre-Manzo, BSc4, Tamara Cibrian-Llanderal, BSc4, Deissy Herrera-Covarrubias, BSc, MSc4, Luz Teresa Espin-Iturbe, DVM, MSc4 & Jorge Manzo, PhD1