Long range effects of MPOA lesion on mating behavior in the male rat

Ginton, Avital; Merari, Ariel

doi:10.1016/0006-8993(77)90507-8

Cited by 84 publications

(20 citation statements)

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“…The defect must lie in the central nervous system, perhaps in the preoptic area of the brain. Several neuroanatomical sexual dimorphisms which depend upon exposure to androgens or oestrogens during infancy have been reported in the preoptic area of the rat (Raisman & Field, 1973;Gorski, Shryne, Gordon & Christensen, 1977), and normal male sexual behaviour in the rat seems to depend on this region of the brain (Davidson, 1966;Christensen & Clemens, 1974;Christensen, Nance & Gorski, 1977;Ginton & Merari, 1977). The absence of ejaculation in the rats treated with testosterone+ADT may therefore be due to a defect in the neuronal organization of the preoptic area.…”

Section: Copulatory Efficiencies and Organ Weights And Measurementsmentioning

confidence: 97%

Effects of the Aromatization Inhibitor Androst-4-Ene-3,6,17-Trione on Sexual Differentiation Induced by Testosterone in the Neonatally Castrated Rat

Booth¹

1978

Journal of Endocrinology

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Groups of rats were castrated on the day of birth (day 1) and injected with testosterone, androst-4-ene-3,6,17-trione (ADT, an inhibitor of aromatization), testosterone + ADT or oil daily from day 1 to day 5. The aromatizable androgen testosterone suppressed both cyclic gonadotrophin secretion, as judged from the absence of corpora lutea in grafted ovaries, and the behavioural response to injections of oestradiol benzoate and progesterone in adulthood. It also stimulated normal development of the penis and ejaculation in behaviour tests carried out after injections of testosterone propionate. The aromatization inhibitor ADT, like oil, did not affect either cyclic gonadotrophin secretion or receptive behaviour, but injections of ADT given at the same time as testosterone significantly reduced the effects of the androgen on both cyclic gonadotrophin secretion and receptive behaviour. Although neonatal administration of ADT did not affect the testosterone-stimulated development of the penis or the ability of the rats to achieve penile intromissions, it did interfere with ejaculation. None of the rats which had been injected with testosterone+ADT ejaculated. These results support the concept that during infancy neural conversion of androgens to oestrogens is important both for the suppression of the female patterns of gonadotrophin secretion and sexual behaviour and for the central organization of normal patterns of male sexual behaviour. Normal completion of the differentiation of the male genital tract appears to be independent of the central organization of masculine patterns of sexual behaviour.

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Section: Copulatory Efficiencies and Organ Weights And Measurementsmentioning

confidence: 97%

Effects of the Aromatization Inhibitor Androst-4-Ene-3,6,17-Trione on Sexual Differentiation Induced by Testosterone in the Neonatally Castrated Rat

Booth¹

1978

Journal of Endocrinology

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“…Unlike the LPOA, for which little data are available concerning its role in reproductive mechanisms, the MPOA has long been implicated in reproductive physiology (Sachs and Meisel, 1988;Giuliano et al, 1995). Bilateral electrolytic (Ginton and Merari, 1977;Kondo and Arai, 1995) or neurotoxic (Hansen et al, 1982) lesions of the MPOA eliminate copulatory behavior, whereas stimulation of this area augments sexual activity (Merari and Ginton, 1975), generates penile erections (Giuliano et al, 1996), and removes a descending inhibition of penile reflexes (Marson and McKenna, 1994). Moreover, the unit activity of certain neurons in this structure increases in association with specific copulatory events (Shimura et al, 1994).…”

Section: The Preoptic Area and Erectile Mechanismsmentioning

confidence: 99%

Role of the Lateral Preoptic Area in Sleep-Related Erectile Mechanisms and Sleep Generation in the Rat

et al. 2000

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Penile erections are a characteristic phenomenon of paradoxical sleep (PS), or rapid eye movement sleep. Although the neural mechanisms of PS-related erections are unknown, the forebrain likely plays a critical role (Schmidt et al., 1999). The preoptic area is implicated in both sleep generation and copulatory mechanisms, suggesting it may be a primary candidate in PS erectile control. Continuous recordings of penile erections, body temperature, and sleep-wake states were performed before and up to 3 weeks after ibotenic acid lesions of the preoptic forebrain in three groups of rats. Neurotoxic lesions involving the medial preoptic area (MPOA) and anterior hypothalamus (n ϭ 5) had no significant effects on either erectile activity or sleep-wake architecture. In contrast, bilateral lesions of the lateral preoptic region, with (n ϭ 4) or without (n ϭ 5) MPOA involvement, resulted in a significant decrease in the number of erections per hour of PS, number of PS-related erections, and PS phases exhibiting an erection. Lesion analysis revealed that the candidate structures for PS erectile control include both the lateral preoptic area (LPOA) and ventral division of the bed nucleus of the stria terminalis; however, lesions of the LPOA were the most effective in disrupting PS erectile activity. LPOA lesioning also resulted in a long-lasting insomnia, characterized by the significant increase in wakefulness and decrease in slow wave sleep (SWS). PS architecture and waking-state erections remained unchanged after lesion in all groups. These data identify an essential role of the LPOA in both PS-related erectile mechanisms and SWS generation. Moreover, higher erectile mechanisms appear to be context-specific because LPOA lesioning selectively disrupted PS-related erections while leaving waking-state erections intact. Key words: sleep-related erections; nocturnal penile tumescence; medial preoptic area; lateral preoptic area; bed nucleus of the stria terminalis; basal forebrain; insomnia; slow wave sleep; paradoxical sleep; REM sleepParadoxical sleep (PS), also known as rapid eye movement sleep, is characterized by several tonic and phasic phenomena, including cortical desynchronization, rapid eye movements, general muscle atonia, and penile erections. Whereas the neural control of PSrelated erections remains unknown, the executive mechanisms generating PS and its other tonic and phasic events are relatively well elucidated and localized within the mesopontine tegmentum and rostral medulla (Sakai 1985;Jones 1991).Using a new technique of chronic penile erection recording in the rat (Schmidt et al., 1995), we recently demonstrated that mesencephalic transections disrupt PS erectile activity even though PS remains otherwise qualitatively intact (Schmidt et al., 1999). These data suggest that forebrain structures rostral to the transection are necessary for the production of PS-related erections. The source of this forebrain control currently is a matter of speculation.Numerous forebrain structures have been implicated in rep...

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“…In rats [1][2][3], cats [4], dogs [51, goats [6], and monkeys [7], lesions of the MPOA eliminate male copulatory responses. It has been proposed that the role of the MPOA is to process sensory information exclusive of sexual arousal [2,8] and that inability to integrate information of a sexual nature as a consequence of lesioning is the cause for observed copulatory defects [1,8].…”

Section: Introductionmentioning

confidence: 99%

Endocrine Correlates of Partner Preference Behavior in Rams1

Resko

Perkins

Roselli

et al. 1996

Biology of Reproduction

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We studied a unique group of rams that would not mate with estrous ewes during extensive testing for sexual behavior. The same rams courted males in preference to females in 30-min sexual preference tests and were classified as male-oriented (n = 6). We compared the following endocrine profiles: systemic steroid concentrations, the capacity of the testes to biosynthesize 17 alpha-hydroxyprogesterone and testosterone from 3H-progesterone in vitro, and the levels of brain aromatase activity (AA) in male-oriented rams vs. rams that were proven breeders and designated as female-oriented (n = 7). After the last behavioral test, sera were collected, and males in each experimental group were killed. Brains and testes were obtained for subsequent determinations of AA and measurements of steroidogenic enzyme activity. All dissections and subsequent assays were performed without knowledge of experimental group assignments. Serum concentration of testosterone (T), dihydrotestosterone (DHT), androstenedione, estrone (E1), and estradiol-17 beta (E2) were determined by RIA. AA was quantified by a 3H2O assay validated for neural tissue of the ram. We studied frontal, parietal and cingulate cortex, cerebellum, hippocampus, olfactory bulb, septum, amygdala, infundibulum-median eminence, and preoptic area (POA). Serum T, E1, and E2 concentrations of female-oriented subjects were significantly higher (p < 0.05) than those in male-oriented subjects (SEM: 1559 +/- 228, 46 +/- 2, and 15 +/- 3 pg/ml vs. 874 +/- 196, 40 +/- 2, and 8 +/- 1 pg/ml serum, respectively). DHT and androstenedione concentrations in the systemic circulation did not differ between groups. Likewise, biosynthesis of labeled T and 17 alpha-hydroxyprogesterone from 3H-progesterone by testicular homogenates in vitro was significantly higher (p < 0.05) in female-oriented than in male-oriented subjects (28.8 +/- 8.1 vs. 12.1 +/- 2.3 mumol.h-1.mg protein-1 for T and 416.9 +/- 100.8 vs. 186.3 +/- 30.7 mumol.h-1.mg protein-1 for 17 alpha-hydroxyprogesterone). The highest level of AA was found in the POA, which was significantly greater in female-oriented than in male-oriented rams (472 +/- 34 vs. 296 +/- 24 fmol 3H2O.h-1.mg protein-1, p < 0.05). AA in other brain areas did not differ between experimental groups. Our data suggest that the testes of the male-oriented ram have reduced capacity for T production. In other species, T controls in situ estrogen formation not only by providing substrate for aromatization but also by up-regulating P450arom mRNA in the POA. Because the POA is part of a neural circuitry that mediates male sexual behavior in many species, we hypothesize that the capacity for aromatization influences sexual orientation of these rams.

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Long range effects of MPOA lesion on mating behavior in the male rat

Cited by 84 publications

References 4 publications

Effects of the Aromatization Inhibitor Androst-4-Ene-3,6,17-Trione on Sexual Differentiation Induced by Testosterone in the Neonatally Castrated Rat

Effects of the Aromatization Inhibitor Androst-4-Ene-3,6,17-Trione on Sexual Differentiation Induced by Testosterone in the Neonatally Castrated Rat

Role of the Lateral Preoptic Area in Sleep-Related Erectile Mechanisms and Sleep Generation in the Rat

Endocrine Correlates of Partner Preference Behavior in Rams1

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