Elsevier

Current Opinion in Neurobiology

Volume 9, Issue 6, 1 December 1999, Pages 751-758
Current Opinion in Neurobiology

Review
Neurobiology of sexual behavior

https://doi.org/10.1016/S0959-4388(99)00034-3Get rights and content

Abstract

Recent advances in the neurobiology of sexual behavior have helped to refine our understanding of the neuroanatomical, neuroendocrine and neurochemical systems that modulate responses to sexual stimulation. Both appetitive and consummatory sexual behaviors have been studied in several laboratory species and in humans using traditional and novel behavioral paradigms. New knowledge has emerged concerning the role of hypothalamic, limbic and brainstem structures, neuropeptides, brain monoamines and nitric oxide in the control of partner preference, sexual desire, erection, copulation, ejaculation, orgasm and sexual satiety. Brain imaging of visually evoked sexual arousal in humans has also been examined.

Introduction

Substantial progress has been made in elucidating the neuroanatomical, neuroendocrine and neurochemical regulation of appetitive and consummatory aspects of sexual behavior. This effort has been aided by the addition of new behavioral paradigms, animal models of drug-induced human sexual dysfunction, and correlative work in humans, especially in the area of brain and hormonal activation by sexual stimuli. This review, which is by no means complete, attempts to provide a framework for some of the exciting research findings that have appeared since August 1998.

Section snippets

Behavioral paradigms

A ‘triad mating paradigm’ was introduced [1••] in which a single male rat is placed into an open field with two sexually receptive female rats. Males trained previously to associate a neutral odor (almond or lemon) with sexual activity ejaculated preferentially with females bearing that odor, despite copulating indiscriminately with both females (Figure 1). This conditioned ejaculatory preference was Pavlovian in nature, as males in random- and explicitly-unpaired control groups did not show

Animal models of human sexual dysfunction

Antidepressant and antihypertensive medications in humans are notorious for their sexual side effects, including the disorders of sexual desire, arousal and orgasm. Sub-chronic and chronic effects of fluoxetine (Prozac, Eli Lilley Incorporated, Indianopolis, USA) have been examined in sexually active female [2] and male [3] rats. Daily fluoxetine administration for one to three weeks reduced lordosis quotients in gonadally intact females in estrus without altering vaginal cyclicity. A similar

Stimulation of sexual desire and arousal

Neural mechanisms associated with motivational aspects of sexual behavior, including the stimulation of erection and ejaculation in sexually active rats, or the stimulation of copulation in sexually sluggish or naive rats, have been examined. Several studies have refined our understanding of the regulation of noncontact erections (NCEs) in male rats, a homologue of psychogenic erection in humans that is stimulated by sex odors from the female. In sexually experienced, castrated male rats, NCEs

Copulation and sexual stimulation

Specific effects of drugs and hormones on consummatory measures of copulation continue to be an important focus of research, as do studies that reveal neuroanatomical activation following particular types of sexual stimulation.

Serotonin (5-HT) systems have been examined, with particular regard to the facilitation of ejaculation produced by the 5-HT1A agonist 8-OH-DPAT. Interactions with DA systems have been examined both in the mPOA [25] and systemically [26]. Regarding female sexual behavior,

Human sexual behavior

Several advances have been made in understanding the relationship between plasma hormone levels and sexual desire, arousal and stimulation. Monthly measures of salivary testosterone were correlated positively with the initiation and rate of sexual intercourse in adolescent males [44]. In aging males, however, the androgen dihydroepiandrosterone (DHEA), much publicized for its ability to improve sexual function and general sense of well-being, had only transient effects in a well-controlled,

Conclusions

The introduction of Viagra (Pfizer, UK) in 1998 marked a resurgence of interest in the neurobiology of sexual function and dysfunction. Thanks to years of progress in understanding basic brain, hormonal and neurochemical mechanisms of copulatory behavior, and recent advances in molecular biology and pharmacology, we stand at a crossroads in the study of sexual behavior. Trends in the past year indicate that more appetitive aspects of sexual desire and arousal are being studied in laboratory

Acknowledgements

The work from the author’s laboratory reported in this review was supported by grants from the Medical Research Council of Canada (MT-13125), Natural Sciences and Engineering Research Council of Canada (OGP-0138878), and Fonds pour la Formation de Chercheurs et l’Aide à la Recherche du Québec (CE-98). The author would like to acknowledge the scientific contributions of James Cantor, Tod Kippin, Wendy Smith, and Carol Coopersmith.

References and recommended reading

Papers of particular interest, published within the annual period of review, have been highlighted as:

  • • of special interest

  • •• of outstanding interest

References (50)

  • L.V. Riters et al.

    Effects of brain testosterone implants on appetitive and consummatory components of male sexual behavior in Japanese quail

    Brain Res Bull

    (1998)
  • L. Matuszewich et al.

    Partial antagonism of 8-OH-DPAT’s effects on male rat sexual behavior with a D2, but not a 5-HT1A, antagonist

    Brain Res

    (1999)
  • J. Rehman et al.

    Modification of sexual behavior of Long–Evans male rats by drugs acting on the 5-HT1A receptor

    Brain Res

    (1999)
  • N. Maswood et al.

    Functional integration among 5-hydroxytryptamine receptor families in the control of female sexual behavior

    Brain Res

    (1998)
  • C.A. Frye et al.

    The neurosteroids progesterone and 3alpha,5alpha-THP, enhance sexual motivation, receptivity, and proceptivity in female rats

    Brain Res

    (1998)
  • J.G. Pfaus et al.

    Appetitive and consummatory sexual behaviors of female rats in bilevel chambers. I: A correlational and factor analysis, and the effects of ovarian hormones

    Horm Behav

    (1999)
  • E.M. Brandling-Bennett et al.

    Paced mating behavior in female rats in response to different hormone priming regimens

    Horm Behav

    (1999)
  • S.M. Ramos et al.

    Protein synthesis in the medial preoptic area is important for the mating-induced decrease in estrus duration in hamsters

    Horm Behav

    (1999)
  • R.D. Romeo et al.

    Pheromones elicit equivalent levels of Fos-immunoreactivity in prepubertal and adult male Syrian hamsters

    Horm Behav

    (1998)
  • D.B. Parfitt et al.

    Fos-immunoreactivity within the extended amygdala is correlated with the onset of sexual satiety

    Horm Behav

    (1998)
  • L.A. Lumley et al.

    Effects of a D1 antagonist and of sexual experience on copulation-induced Fos-like immunoreactivity in the medial preoptic nucleus

    Brain Res

    (1999)
  • C.A. Frye et al.

    Progesterone has rapid and membrane effects in the facilitation of female mouse sexual behavior

    Brain Res

    (1999)
  • S. Honda et al.

    Disruption of sexual behavior in male aromatase-deficient mice lacking exons 1 and 2 of the cyp19 gene

    Biochem Biophys Res Commun

    (1998)
  • T. Kruger et al.

    Neuroendocrine and cardiovascular response to sexual arousal and orgasm in men

    Psychoneuroendocrinology

    (1998)
  • T.K. Kippin et al.

    Olfactory conditioning of sexual behavior in the male rat

    J Comp Psychol

    (1998)
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