Suppression of the lordosis reflex of female rats by efferents of the medial preoptic area

Takeo, Teruko; Chiba, Yoshinobu; Sakuma, Yasuo

doi:10.1016/0031-9384(93)90258-h

Cited by 64 publications

(30 citation statements)

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“…MPO plays a gender-dependent role in reproductive behavior. In females, bilateral lesions of the MPO facilitate the occurrence of lordosis (Powers and Valenstein, 1972;Nance et al, 1977;Rodriguez-Sierra and Terasawa, 1979;Lisk and MacGregor, 1982;Hoshina et al, 1994); chemical or electrical stimulation of MPO suppresses it (Moss et al, 1974;Zasorin et al, 1975;Pfaff and Sakuma, 1979;Takeo et al, 1993). By contrast, in males MPO lesions completely abolish mounting, intromission, and ejaculation, whereas stimulation of this region induces copulation (Heimer and Larrson, 1966;Lisk, 1966;Malsbury et al, 1981;Hansen et al, 1982;Arendash and Gorski, 1983;Edwards and Einhorn, 1986).…”

Section: Reproductivementioning

confidence: 99%

“…Taken together, these results suggest that the MPO + PAG + RVM projection constitutes a functional pathway. This circuit may coordinately regulate neuroendocrine, motor, and autonomic adjustments necessary for the elaboration of sexual behaviors.Key words: reproduction; antinociception; cardiovascular regulation; brainstem; sexual behavior; immunohistochemistryThe medial preoptic area (h/[PO) is a sexually dimorphic structure Simerly et al, 1984;Bloch and Gorski, 1988) that plays a pivotal role in sexual behavior and neuroendocrine function (Lisk, 1966;Powers and Valenstein, 1972;Pfaff and Sakuma, 1979;Hansen et al, 1982;Arendash and Gorski, 1983;Kalra and Kalra, 1983;Docke et al, 1984;Sachs and Meisel, 1988;Simerly et al, 1990;DonCarlos et al, 1991;Takeo et al, 1993;Hoshina et al, 1994). We recently reported that MPO robustly innervates the midbrain periaqueductal gray (PAG) (Rizvi et al, 1992) and terminates in discrete, longitudinally organized columns running through the rostrocaudal axis of PAG.…”

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confidence: 99%

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Medial preoptic area afferents to periaqueductal gray medullo-output neurons: a combined Fos and tract tracing study

et al. 1996

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We have shown recently that the medial preoptic area (MPO) robustly innervates discrete columns along the rostrocaudal axis of the midbrain periaqueductal gray (PAG). However, the location of PAG neurons responsive to MPO activation is not known. Anterograde tract tracing was used in combination with Fos immunohistochemistry to characterize the MPO -+ PAG pathway anatomically and ,functionally within the same animal. Focal electrical or chemical stimulation of MPO in anesthetized rats induced extensive Fos expression within the PAG compared with sham controls. Fos-positive neurons were organized as 2-3 longitudinal columns. The organization and location of these columns overlapped remarkably well with the distribution of fibers and terminals in PAG labeled by Phaseolus vulgaris leucoagglutinin (PHA-L) injected into the same MPO stimulation site. This indicates that MPO inputs may terminate on the soma or proximal dendrites of neurons exhibiting elevated Fos. A second series of experiments investigated whether MPO stimulation excited PAG neurons with descending projections to the medulla. Retrograde labeling of PAG neurons projecting to the medial and lateral regions of the rostroventral medulla (RVM) was combined with MPO-induced Fos expression. The results showed that a substantial population (3743%)of Fos-positive PAG neurons projected to the ventral medulla. This indicates that MPO stimulation engages PAG-medullary output neurons. Taken together, these results suggest that the MPO + PAG + RVM projection constitutes a functional pathway. This circuit may coordinately regulate neuroendocrine, motor, and autonomic adjustments necessary for the elaboration of sexual behaviors.Key words: reproduction; antinociception; cardiovascular regulation; brainstem; sexual behavior; immunohistochemistryThe medial preoptic area (h/[PO) is a sexually dimorphic structure Simerly et al., 1984;Bloch and Gorski, 1988) that plays a pivotal role in sexual behavior and neuroendocrine function (Lisk, 1966;Powers and Valenstein, 1972;Pfaff and Sakuma, 1979;Hansen et al., 1982;Arendash and Gorski, 1983;Kalra and Kalra, 1983;Docke et al., 1984;Sachs and Meisel, 1988;Simerly et al., 1990;DonCarlos et al., 1991;Takeo et al., 1993;Hoshina et al., 1994). We recently reported that MPO robustly innervates the midbrain periaqueductal gray (PAG) (Rizvi et al., 1992) and terminates in discrete, longitudinally organized columns running through the rostrocaudal axis of PAG.PAG plays a key role in antinociception (Reynolds, 1969;Liebeskind et al., 1973;Oliveras et al., 1974;Behbehani and Fields, 1979; Lovick, 3985;Morgan and Liebeskind, 1987;Reichling et al., 1988;Lovick, 1990), cardiovascular control (Lovick, 1985;Carrive et al., 1987;Carrive et al., 1988;Carrive et al., 1989a;Lovick, 1990;Verberne and Guyenet, 1992;Murphy et al., 1994a;Murphy et al., 1995), and many of the same neuroendocrine and reproductive functions as MPO (Pfaff and SchwartzGiblin, 1988;Ogawa et al., 1991;Shipley et al., 1995). PAG neurons involved in these functions also are ...

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Section: Reproductivementioning

confidence: 99%

mentioning

confidence: 99%

Medial preoptic area afferents to periaqueductal gray medullo-output neurons: a combined Fos and tract tracing study

et al. 1996

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“…The present results emphasize that estrogen elicits lordosis reflex via excitation of efferent VMN neurons to the CG, whereas estrogen inhibits neurons in the preoptic and ventral tegmental continuum to exert the same behavioral effect [42][43][44]. Electrical stimulation of the VMN enhanced the reflex [10].…”

Section: Methodmentioning

confidence: 73%

Temporal Coincidence between the Excitation of Ventromedial Hypothalamic Efferents and the Induction of Lordosis Reflex in Ovariectomized Estrogen-Primed Rats.

1998

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Abstract. The temporal changes in excitability in ventromedial hypothalamic neurons which project to the midbrain central gray caused by chronic estrogen exposure were measured in ovariectomized rats. In 66 urethane-anesthetized animals which had either no capsule, or had a capsule containing estrogen implanted for 24 h, 48 h, 72 h or 96 h, 189 antidromic action potentials were recorded in the ventromedial hypothalamus (VMN) in response to stimulation of the midbrain central gray (CG). The antidromic activation threshold was lower in 40 recordings made from the VMN in the 72-h or 96-h group than in 67 from the no-treatment, 24-h or 48-h group. The decrease in the threshold coincided with the emergence of the lordosis reflex. In a separate cohort of ovariectomized rats, any absence of estrogen for 2-48 h before and during the measuring abolished the neuronal as well as the behavioral effects at 72 h. The results suggest that the lordosis reflex induced by estrogen alone depends on the excitation of VMN efferents to the CG. In addition, the indispensability of estrogen at the time of electrophysiological and behavioral evaluation indicates that a certain direct neural action of estrogen is involved in the behavioral activation. Implants of minute amounts of crystalline estradiol showed that the ventromedial nucleus of the hypothalamus (VMN) is the principal site for estrogen action to facilitate the lordosis reflex [9]. Stimulation and lesion studies have shown that the VMN facilitates the lordosis reflex via its descending projection to the midbrain central gray (CG) [10][11][12]. Estrogen-induced excitation of VMN neurons with axons to the CG in ovariectomized rats [13][14][15] corroborates the behavioral results. Experiments on neonatally gonadectomized males and neonatally androgenized females, in which the neural effects of estrogen in parallel with its behavioral capability to induce the lordosis reflex [16], provide additional evidence for the association of the neural effect of estrogen with facilitation of the lordosis reflex.In the present study we attempted to establish a

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“…This suggests that the lordosis inhibitory system of the LS projects to the lower brain stem (the mesencephalic central gray) through the MPOA [5, 6]. Electrical stimulation of the MPOA suppressed lordosis after a transection between the LS and MPOA [7], and an axon-sparing lesion in the MPOA by ibotenic acid enhanced lordosis [8], suggesting that the MPOA per se can also inhibit lordosis in female rats. In addition, it was found that an ibotenic acid lesion in the MPOA also increased the rate of male rejection and decreased the display of soliciting behavior, such as ear-wiggling and hopping [8].…”

Section: Introductionmentioning

confidence: 99%

Differential Regulation of Female Rat Olfactory Preference and Copulatory Pacing by the Lateral Septum and Medial Preoptic Area

2005

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We examined the effect of bilateral radiofrequency lesions in the lateral septum (LS) or medial preoptic area (MPOA) on olfactory preference (time spent sniffing odors derived from either a stud or castrated male) and pacing behavior (paracopulatory behavior in a cage with a compartment inaccessible to males) in ovariectomized rats following different hormonal regimes. Sham-operated and LS-lesioned females, but not MPOA-lesioned females, preferred odors from the stud males to the castrated males. MPOA lesions significantly decreased total nose-poking time, compared to that of sham-operated females. When mounted by stud males, both LS- and MPOA-lesioned females showed significantly higher lordosis quotients than sham-operated females. On the other hand, LS-lesioned females spent a significantly longer time in the male compartment, and stayed with the males even after they were mounted. These results suggest that the LS and MPOA play different roles in the sociosexual activity in female rats, and that the two regions exert an inhibitory influence on lordosis.

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Suppression of the lordosis reflex of female rats by efferents of the medial preoptic area

Cited by 64 publications

References 39 publications

Medial preoptic area afferents to periaqueductal gray medullo-output neurons: a combined Fos and tract tracing study

Medial preoptic area afferents to periaqueductal gray medullo-output neurons: a combined Fos and tract tracing study

Temporal Coincidence between the Excitation of Ventromedial Hypothalamic Efferents and the Induction of Lordosis Reflex in Ovariectomized Estrogen-Primed Rats.

Differential Regulation of Female Rat Olfactory Preference and Copulatory Pacing by the Lateral Septum and Medial Preoptic Area

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