Respiratory responses and rating of perceived exertion of severely obese adolescents during continuous and intermittent graded walking protocols: Application to cardiorespiratory field tests

During 20 m shuttle tests, obese adolescents may have difficulty achieving maximum cardiorespiratory performance due to the presence of braking-relaunch phases (BRP). Nineteen obese adolescents aged 15.2 ± 1.5 years (body mass index [BMI] = 39.7 ± 5.9 kg.m^-2) performed three graded walking exercises on a 50 m track at speeds between 3 and 6 km/h: a continuous-straight-line protocol (C), a continuous protocol that required turning back every 30 sec (C-BRP) and an intermittent protocol that consisted of successively walking then resting for 15 sec (15-15). Oxygen uptake (VO₂), aerobic cost of walking (Cw), ventilation (VE) and rating of perceived exertion (RPE) were measured at each stage during the protocols. During C-BRP, the responses were not significantly higher compared with C (p > 0.30). During 15-15, the VO₂, Cw and VE were ~ 15 to 25% lower than during C beginning at 4 km/h (p < 0.05). In obese adolescents, the respiratory impact of sudden directional changes during the 20 m shuttle-type test appeared to be minor at walking speeds. During the 15-15 test, the intensity increases more progressively, and this design may encourage obese adolescents to walk further than during a continuous test.

Stabilizing Entanglement via Symmetry-Selective Bath Engineering in Superconducting Qubits

Bath engineering, which utilizes coupling to lossy modes in a quantum system to generate nontrivial steady states, is a tantalizing alternative to gate- and measurement-based quantum science. Here, we demonstrate dissipative stabilization of entanglement between two superconducting transmon qubits in a symmetry-selective manner. We utilize the engineered symmetries of the dissipative environment to stabilize a target Bell state; we further demonstrate suppression of the Bell state of opposite symmetry due to parity selection rules. This implementation is resource efficient, achieves a steady-state fidelity F=0.70, and is scalable to multiple qubits.

Are the Amygdaloid Projections to the Hypothalamic Ventromedial Nucleus Involved in Estrous Rhythm Regulation in the Female Rat?

The aim of this investigation was to determine whether the corticomedial amygdaloid nucleus (CMA) and its projections to the hypothalamic ventromedial nucleus (VMN) were involved in the regulation of estrous rhythm by the VMN in the rat. It is known (Carrer et al., 1973-1974) that partial VMN lesions caused the occurrence of either 5-day or alternate 4- or 5-day cycles in about 50% of 4-day cyclic female rats and that large lesions induced cycle prolongation in most of the operated animals while hypothalamic dorsomedial nucleus (DMN) lesions left estrous rhythm unmodified. CMA lesions in 4-day cyclic female rats caused the occurrence of either 5-day or alternate cycles with sequence of 4, 5, 4 days, more frequently than in their sham operated counterparts (15/20 vs 3/20). Stria terminalis (ST) lesions placed at its emergence from the CMA or at its horizontal course over the internal capsule induced a higher proportion (10/14 and 9/16, respectively) of females to display changes in cycle duration than did sham operated and unoperated controls as well (10/32 and 7/29, respectively). Combined partial VMN and ST lesions resulted in a 24 hours cycle prolongation or alternate 4- and 5-day cycles in a greater number of females than in those bearing small VMN lesions only (15/18 vs 22/40). A noticeable proportion of CMA, ST and ST + small VMN lesioned females offered more or less prolonged diestrous periods immediately following surgery before resuming estrous cyclicity. It was suggested that the CMA neurons which project fibers to the VMN via the ST are implicated in estrous rhythm regulation in the rat.

[Results of an ambulatory respiratory rehabilitation program: observations in 100 COPD patients]

INTRODUCTION

Respiratory rehabilitation is a multidisciplinary approach enabling personalized management adapted for each patient's handicap.

METHOD

Our ambulatory program includes twenty sessions per week (four half-days/week) for respiratory training at the ventilatory threshold, respiratory physical therapy, and health education. One hundred COPD patients participated in this retrospective study: mean age 62.1 +/- 9.6 years; FEV1: 1.51 +/- 0.66 (53 +/- 22% of theoretical).

RESULTS

At the ventilatory threshold, there was a significant 9% gain in oxygen uptake and a 31% gain in power. At maximal exercise, there was a 6% improvement in oxygen uptake, 21% gain in power, and 7% gain in tidal volume (p<0.05). Walking distance improved 15% (+ 61 m). Quality of life was also improved significantly, with loss of 8 points on the Saint-George's Hospital respiratory questionnaire.

CONCLUSION

This study demonstrates the beneficial effect of respiratory rehabilitation in terms of improved tolerance to exercise and improved quality of life for COPD patients.

[Fortuitously discovered lung nodules]

Pulmonary nodular amyloidosis is a rare entity. We report a new case where multiple nodules suggested, first, a neoplastic process. Clinical and radiological findings were non specific. Positive diagnosis was established at pathology.

[Pleural sarcoidosis. Course of an unusual localization after corticosteroid treatment]

We report the case of a 69-year-old woman investigated for suspected pleuropneumopathy. Thoracoscopy led to the diagnosis of sarcoidosis with pleural involvement. This case illustrates an uncommon localization of sarcoidosis and its clinical course after corticosteroid treatment.

[Non-invasive ventilation in acute or chronic respiratory failure: a comparison of volumetric ventilation]

BACKGROUND

Although experience acquired with non-invasive ventilation is recent, it is often proposed in selected patients with acute respiratory failure occurring in a background of chronic airflow obstruction. Barometric or volumetric techniques can be used.

PATIENTS AND METHODS

We compared tolerance and efficacy of inspiration assist (IA) using a preset pressure and volume-controlled ventilation (VC). Twelve patients with chronic airflow obstruction were randomized to IA (n = 7) or VC (n = 9) mode and ventilated with the appropriate mask.

RESULTS

Tolerance was equivalent for the two groups although hypercapnia fell more in the IA group, particularly after 24 h ventilation (p < 0.03), after three days (p < 0.05), and at complete weaning (p < 0.03). Correction of pH was significantly more rapid in the IA group than in the VC group (p < 0.05 at 24 h). There was no difference in the number of days of ventilation, total ventilation time, or length of hospital stay. Success of non-invasive ventilation, defined as the control of acute respiratory failure without recourse to endotracheal ventilation, was similar in the two groups (86% in group IA and 60% in group VC). Two of the 5 patients in the VC group and one of the 7 in the IA group required intubation.

[Sarcoidosis in a patient with Crohn disease]

Extra-intestinal manifestations of inflammatory bowel disease (Crohn's disease) are frequent although pulmonary signs are uncommon. We report the case of a patient with sarcoidosis and inflammatory bowel disease and discuss the common features of these two diseases.

[Surgical emergency disclosing sarcoidosis. Apropos of a case]

Sarcoidosis is a diffuse granulomatosis predominately with mediastino-pulmonary localizations. A wide range of extrathoracic localizations can also occur and when they are the initial manifestation, may lead to misdiagnosis. We observed a rare case of peritoneal sarcoidosis revealed by a surgical emergency.

[Severe hypoxemia in cirrhosis]

Various respiratory signs (other than infectious pathology), either very frequent and mild or very rare but with a poor prognosis, can be observed in cirrhotic subjects. Hypoxemia raises the greatest diagnostic problems in these subjects. The poor homogeneity of ventilation-perfusion ratios is the most commonly proposed cause of hypoxemia in cirrhosis. In such cases, hypoxemia is typically moderate (60-80 mmHg). Conversely, anatomical shunts, especially intrapulmonary ones, account for severe hypoxemia (< 60 mmHg). We are reporting about the case of a severe form of hypoxemia without anatomical shunt, caused by an anomalous ventilation-perfusion ratio in a female patient with ethylic cirrhosis.

Bisexual behavior in the male rat: influence of masculine sexual activity on the display of lordosis behavior

Sexually inexperienced male Wistar rats (strain WI in our colony) known to very infrequently display spontaneous lordosis behavior (Schaeffer et al., 1990b) were used. A first group was tested four times at 5-day intervals for lordosis with vigorous stimulus males (heterotypic sexual behavior), immediately following testing for masculine sexual activity with highly receptive females (homotypic sexual behavior). A small number of animals displayed lordosis during the first test, but more and more animals displayed this behavior from the first to the fourth test. There was no relationship between the degree of masculine sexual activity--intromission without ejaculation or ejaculation--and the occurrence of lordosis behavior. A second group was tested only once for both masculine sexual activity and lordosis behavior as above and afterwards three times at 5-day intervals for lordosis behavior in the absence of any previous testing for masculine sexual activity. A few animals displayed lordosis during their first test. As compared to the first group, the animals which had not displayed lordosis in the first test never showed lordosis responses in the following tests. It is concluded that both homotypic and heterotypic sexual interactions are required for the display of lordosis behavior in the strain of Wistar rats used in this study.

Interactions of testosterone with the olfactory system in the display of mounting behavior in the female rat

Adult ovariectomized female rats received a testosterone propionate (TP) silastic implant (day 0) and were subsequently tested for mounting behavior. The number of females displaying mounting behavior increased from day 2 (0%) to day 14 (94%) following testosterone implantation. Olfactory bulbectomy (OB) performed on day -7 or on day +14 reduced the number of females that mounted on day +16 as compared to sham counterparts. However, the number of females displaying mounting behavior was significantly higher when OB was performed on day +14 than on day -7. Peripheral anosmia induced by ZnSO4 instillation, either with multiple instillations beginning on day -8 before TP implant or with a single injection on day +14, equally impaired mounting behavior on day +16. These results, which further confirm the role of the olfactory system in facilitating the display of mounting behavior in the female rat, suggest an olfaction-testosterone interaction.

Induction of progestin receptors in the mediobasal hypothalamus of gonadally intact male rats primed with estrogen in relation to display of lordosis behavior

The purpose of this study was to determine whether the effects of estrogen on lordosis behavior in the male rat were related to the number of progesterone (P) receptors in the mediobasal hypothalamus (MBH) and/or dependent on blood P concentration. Two groups of gonadally intact male rats were given five successive doses of 1.0 or 2.5 micrograms estradiol benzoate (EB) and tested for lordosis behavior with a male stimulus at the end of the treatment. One month later they were again injected with EB and sacrificed under the same temporal schedule, but they were not tested for lordosis so as to prevent any emotionally stressful effects of intermale cohabitation. The males given 2.5 micrograms EB more frequently displayed lordosis responses to male mounts than those receiving 1 microgram EB, with a parallel increase in the number of MBH P receptors. The total number of MBH P receptors also appeared to be higher in the animals that displayed lordosis responses (lordosis group) than in those which did not (no lordosis group). In contrast, the display of lordosis behavior was negatively correlated with blood P concentration. Comparing MBH P receptors and blood P values in the EB treated and in nonhormonally treated gonadally intact animals which had been selected for either ability or inability to spontaneously display lordosis behavior, we observed that (1) EB was capable of increasing the number of MBH P receptors in the male rat; and (2) in the absence of EB treatment blood P values were higher in the animals showing lordosis than in those which did not. These data are discussed with respect to observations made in castrated male rats and in ovariectomized females.

Inhibitory effects of centrally and peripherally induced anosmia on mounting behavior in the female rat

Adult ovariectomized female rats received a testosterone-propionate (TP)-filled silastic implant and were tested for mounting behavior seven days later. Exposure to estrous female urine but not to urine from ovariectomized females increased the number of TP-treated females that displayed mounting behavior. Olfactory bulb removal on its own and peripheral anosmia induced by intranasal ZnSO4 application impaired mounting behavior. These results are discussed with respect to the effects of anosmia on copulatory behavior in the male.

Lordosis behavior in intact male rats: effects of hormonal treatment and/or manipulation of the olfactory system

The aim of this study was to investigate the olfactory mechanisms regulating the display of lordosis behavior in intact Wistar male rats bred in our colony. Gonadally intact males show a low capacity to respond by lordosis to male mounts and were insensitive to manipulations of the olfactory system (exposure to the odor of male urine or accessory bulb removal (AOBR)) which have been previously shown to facilitate the display of lordosis behavior in orchidectomized animals primed with ovarian hormones. Treatment with either estradiol benzoate (EB) or EB and progesterone (P) consecutively did not render these gonadally intact animals sensitive to the effects of AOBR. By contrast exposure to male urine was capable of facilitating the display of lordosis behavior in intact male rats given EB + P consecutively. These results are discussed in the light of previous findings showing that (1) two inhibitory structures, the accessory olfactory bulb and the septal and preoptic areas, are involved in the control of lordosis behavior in the male rat; (2) the effects of olfactory cues on the display of lordosis behavior are dependent on the action of both EB and P in orchidectomized animals.

Lordosis behavior in male rats after lesions in different regions of the corticomedial amygdaloid nucleus

The aim of the experiment was to study the effects of stereotaxic lesions of the anterior and the posterior regions of the corticomedial amygdaloid nucleus (CMN) on the display of lordosis behavior by the male rat. Animals were orchidectomized as adults and given estradiol benzoate and progesterone (P) sequentially. Sexual behavior testing was performed by 9 +/- 1 hr after P injection. Lesions placed into the posterior region of the CMN significantly decreased the proportion of animals showing lordosis behavior as compared to sham-operated and control animals. By contrast lesions in the anterior region of the CMN did not cause any changes in the proportion of animals displaying lordosis but markedly increased the lordosis quotient (LQ) of responding animals. The CMN was then concluded to exert a dual control in the display of lordosis behavior in the male rat with a posterior region regulating the willingness of animals to display lordosis behavior and rostral region subserving inhibitory mechanisms related to the sexual performance (LQ values).

Prepubescent hormonal control of the development of accessory olfactory bulbs in the male rat

The effects of androgen treatment (TP) from postnatal day 20 (P20) onwards on the accessory olfactory bulbs' (AOB) development were studied in rats orchidectomized at birth (PO) or on P20. TP failed to restore impaired AOB development in the rats castrated at PO but completely restored AOB development in those castrated at P20. Androgen secretion during both the perinatal and prepubescent periods appeared to be critical for male AOB development.

Lordosis inhibiting effects of endogenous progesterone in the male rat primed with estrogen

The aim of this study was to investigate the mechanisms involved in the inhibitory action of progesterone on estrogen-induced facilitatory effects of estradiol benzoate on lordosis behavior in the male rat. Intact adult male rats were given 1) 25 micrograms estradiol benzoate (EB) and 100 micrograms progesterone (P) at an interval of 42 hr. EB injected animals served as controls 2) EB followed by 3 doses of 400 micrograms dexamethasone (DEXA) and P as above. EB + DEXA injected animals served as controls. Testing for lordosis behavior was performed by 50 +/- hr after EB injection. A significant decrease in the number of the males displaying lordosis in response to the mounts of stimulus males resulted from P injection following EB treatment as compared to EB controls. DEXA treatment significantly reduced the number of EB animals showing lordosis responses but completely prevented the inhibitory effects of exogenous P to occur. Blood P values appeared to be significantly lower in EB + DEXA males than in their EB counterparts. The results provide evidence that endogenous P is involved in the display of lordosis behavior by EB-treated intact males. They mainly suggest that the effects of exogenous P on estrogen-induced lordosis behavior in the intact male rat result from sequential inhibitory mechanisms involving exposure of the animals to the successive action of endogenous and exogenous P.

Changes in estrogen receptors in the mediobasal hypothalamus mediate the facilitory effects exerted by the male's olfactory cues and progesterone on feminine behavior in the male rat

The purpose of this study was to determine whether facilitory effects exerted by olfactory cues on lordosis behavior in the male rat involved changes in estradiol receptors at the hypothalamic level. Male rats were orchidectomized as adults. They were given either 25 micrograms estradiol benzoate (EB) alone or 25 micrograms EB and 100 micrograms progesterone (P) sequentially and exposed or not to the odor of male urine. Some of them were tested for lordosis behavior at 8 h after P. The other ones were killed 4 h after P and used for estradiol (E2) and P receptor assay in mediobasal hypothalamus (MBH). Olfactory cues were shown to increase the number of E2 receptors in both the animals given EB or EB + P. Progesterone as such appeared to be capable of increasing the number and the rate of occupancy of E2 receptors. A population of constitutive and estrogen-inducible P receptors was detected in the MBH. Since only the animals given EB + P were shown to be sensible to the facilitory effects of male urine on lordosis behavior, it may be assumed that E2 and P on one hand and olfactory cues on the other exert cumulative effects at the level of the MBH and that both a high level and a high rate of occupancy of E2 receptors are necessary for the olfactory cues to facilitate the display of lordosis behavior in the male rat.

Estradiol involvement in the luteolytic action of LH during the estrous cycle in the rat

The study was undertaken to examine LH, prolactin (Prl) and estradiol involvement in the control of corpus luteum function during 4-day cycle in the female rat. A potent LHRH antagonist (Antag) and bromocriptine (BRC) were used to induce LH and Prl deprivation in 4-day cyclic rats. Both drugs were administered after the occurrence of LH and Prl release on the afternoon of proestrus. Blood progesterone (P) concentration on diestrus 1 at 24:00 hr was similar in Antag, Antag + BRC and BRC-treated animals and did not differ from P values in control females. It was then concluded that neither LH nor Prl were necessary for the corpus luteum to achieve its stage of maximal activity during the night from diestrus 1 to diestrus 2. By contrast higher P values were observed on diestrus 2 at 12:00 hr in Antag-treated rats than in those given Antag + BRC, BRC or in the controls. When given on diestrus 1 evening estradiol benzoate completely prevented this effect of Antag to occur in LH and Prl deprived females. These results allow to hypothesize that LH exerts luteolytic effects during the diestrous period of the cycle and also suggest a possible involvement of estradiol in the regression phase of the corpus luteum.

Estrous cycle lengthening by pentobarbital in the rat: prolactin involvement

Pentobarbital lengthens the estrous cycle when injected on diestrus 1 afternoon in the 4-day cyclic female rat. The present study was undertaken to elucidate the mechanisms involved. Bromocriptine (2.5 mg/kg sc) given 30 min before pentobarbital (30 mg/kg ip) prevented the effects of pentobarbital on both cycle lengthening and progesterone levels in diestrus 2. Serum prolactin concentrations rose 10 min after pentobarbital injection, peaked at 30 min, and returned to control values after 60 min. Our results suggest that pentobarbital-induced cycle lengthening is due to a high progesterone production on diestrus 2 morning related to the luteotropic action of prolactin.

Sexual differences in the development of accessory olfactory bulbs in the rat

The aim of this investigation was 1) to compare the development of AOB in male and female rats before birth, early after birth, and at later stages of sexual immaturity and maturity 2) to examine the effects of early and delayed castration after birth on AOB development in the male rat. A significant increase of the surface area of AOB was observed in both sexes from birth until postnatal day 7, but AOB was found to be larger in males than in females. From the end of the first postnatal week AOB stopped growing until day 40 in both males and females. After this time AOB resumed its development until day 60 in males, while no changes occurred in females over the same period. Castration of males at birth or six hours later impaired development of AOB. Castration of males on postnatal days 20 or 30 also impaired AOB development until day 60. The results strongly suggest that the development of AOB in the male rat is dependent on the two well known "perinatal" and "adult" phases of the endocrine activity of the testes.

Facilitory effects of olfactory cues emitted by estrous females on mounting behavior in the female rat

Adult ovariectomized rats were implanted with testosterone propionate-filled silastic capsules and exposed to the odor of urine collected from ovariectomized rats made estrous by estrogen treatment. When caged with highly receptive females these androgenized female rats displayed more frequent mounting behavior with pelvic thrusting than their nonexposed counterparts (25/31 vs. 20/39). Olfactory environment may then be considered as a modulatory factor of heterotypic sexual behavior in the female rat.

Stress-related effects on the secretion of progesterone by the adrenals in castrated male rats presented to stimulus males. Involvement of oestrogen

Rats were orchidectomized (ORCH) as adults and given successive doses of 0.5 microgram or 1.0 microgram of oestradiol benzoate (EB) combined or not with dexamethasone (DEXA) at the end of oestrogen treatment; successive doses of olive oil. They were presented to stimulus males on the day of the last EB injection and decapitated immediately after the behavioural test. Animals given EB or olive oil only served as controls. There was a significant rise in blood progesterone concentration in animals given 0.5 and 1.0 microgram EB as compared with oil-treated animals. A higher blood progesterone concentration was observed at the end of the behavioural session in oil-treated and 0.5 microgram EB-treated ORCH rats than in their isolated counterparts, an effect which appeared not to dependent on lordosis responses to mounting attempts of the males. DEXA completely suppressed the rise in blood progesterone concentration in oestrogenized ORCH rats presented to stimulus males. Presentation of ORCH rats to stimulus males was then concluded to constitute a stressful condition capable of inducing adrenocortical progesterone secretion in ORCH animals.

Effects of ventromedial nucleus lesions on the display of lordosis behavior in the male rat. Interactions with facilitory effects of male urine

Previous observations showed that exposure to the odor of male urine prior to mating could enhance the display of lordosis behavior in male rats feminized with ovarian hormones. This study was performed to determine in feminized male rats whether the control of lordosis behavior by the olfactory system was mediated by the ventromedial nucleus (VMN) of the hypothalamus. Male rats were orchidectomized (ORCH) as adults and primed with 25 micrograms estradiol benzoate (EB) and 150 micrograms progesterone (P) 40 hr apart. Lordosis behavior was tested 9 +/- 1 hr after P injection. VMN lesions were shown to completely suppress the display of lordosis behavior as compared to sham VMN operated and dorsomedial nucleus (DMN) lesioned animals. Exposure of feminized rats to the odor of male urine by 9 +/- 1 hr before mating significantly increased the proportion of ORCH rats that displayed lordosis behavior in response to male mounts. This effect was abolished by VMN lesions but was maintained in the sham VMN operated and DMN lesioned animals. These results were discussed in the light of the present knowledge on the neuroendocrine and olfactory structures which mediate lordosis behavior in the male rat.

Testosterone-induced oestrous cycle blockade in the rat: no evidence for prolactin involvement

The relation between testosterone-induced oestrous cycle disruption and prolactin (Prl) secretion was studied in the female rat. Testosterone propionate (TP) injection on dioestrus 2 (day 0) of 4-day cycles induced cycle interruption for 12 days. A diurnal pattern of Prl secretion was observed from day 1 to day 6 with high levels in the afternoon and low levels in the morning. Cycle interruption also occurred in TP treated females given a dose of bromocriptine (BRC) known to completely block Prl secretion. Impairment of follicular growth resulted from TP treatment and from TP and BRC treatment as well. Until resumption of prooestrous, the follicular size did not exceed that noted during the dioestrous period of the cycle. Despite resumption of follicular growth from day 9 until day 14, ovulation only took place in a small number of animals. These results indicate that the antigonadotropic effects of Prl were not responsible for cycle disruption in our experimental model and that other mechanisms were in itself sufficient for the disruption. This was discussed in the light of previous findings in our laboratory.

Endogenous progesterone and lordosis behavior in male rats given estrogen alone

Male rats castrated as adults were given successive doses of estradiol benzoate (EB) combined or not, with dexamethasone (DEXA) at the end of estrogen treatment. Two experiments were done to determine if progesterone (P) of adrenocortical origin was involved in the display of lordosis behavior under these experimental circumstances. There was a significant rise in blood P concentration in animals given 0.5 and 1.0 microgram EB when compared with oil-control injected animals, an effect which was completely suppressed by DEXA treatment. An increase in the proportion of estrogen treated animals displaying lordosis responses to male mounts was found with increasing doses of EB and paralleled the effects of EB on P adrenocortical secretion. However, the number of feminized animals given 1 microgram EB + DEXA was reduced to the level corresponding to the effects of 0.5 microgram EB on lordosis behavior. These data show that the secretion of P by the adrenals is involved in the expression of lordosis behavior in castrated male rats primed with repeated doses of estrogen.

Accessory olfactory bulb lesions and lordosis behavior in the male rat feminized with ovarian hormones

Orchidectomized rats were given estrogen and progesterone and tested for feminine behavior in the presence of a mounting male after accessory olfactory bulb removal (AOBR). Complete AOBR caused a rise in the number of estrogen-progesterone-treated male rats responding by lordosis behavior to male mounts as compared to controls and sham-operated animals. By contrast, LQ scores did not appear to differ in these three groups of animals. The results are discussed in terms of involvement of the main and the accessory olfactory systems in the regulation of feminine behavior in the male rat.

Olfactory environment and coitus-induced ovulation and/or luteinization in the cyclic female rat

The role of pheromones in the process of ovulation and/or luteinization induced by coitus was studied in female rats primed with estradiol benzoate (EB) and early mated during 4-day cycles. The effects of coitus were evaluated by using 1) the proportion of females displaying postovulatory corpora lutea (POCL) and/or luteinized unruptured follicles (LUF), and 2) the ovulation coefficient (OC) computed in each female by dividing the number of POCL by the total number of POCL and LUF. A greater proportion of females displayed ovulation and/or luteinization following coitus than those given EB only. This proportion was slightly but significantly increased when females were exposed to bedding soiled with 5 ml of male urine prior to mating, an effect prevented by complete olfactory bulbectomy. However, in the females given EB only, the pheromonal stimulus remained inefficient. Weak ovulatory effects of coitus, as assessed by low OC values, were noted whether the females were exposed or not to male urine. An increase in the frequency of lordosis occurred after olfactory bulbectomy, but no significant changes in OC values were observed in this experimental group. It was concluded that pheromones, act as a primer on the neuroendocrine mechanisms governing ovulation in the cyclic female rat, as in other species of rodents.

Olfactory environment and early mating behavior in the cyclic female rat

The objectives of this study were to examine the effects of olfactory cues from the male and of olfactory bulb removal on early mating behavior in sexually inexperienced diestrous female rats primed with estrogen. Four-day cyclic rats isolated from the male were given either 2.5 micrograms or 10 micrograms estradiol benzoate (EB) and presented to stimulated males in the late afternoon of diestrus 2 between 18:00 and 19:00 for a 10 min sexual behavioral session. Dose-dependent effects of estrogen were observed since 10 micrograms EB significantly increased the proportion of females displaying early mating as compared with those given 2.5 micrograms EB. Olfactory bulb removal prior to estrogen treatment caused a rise in the number of females which mated early with respect to the non bulbectomized controls. Exposing the females to bedding soiled with male urine on diestrus 2 at 10:00 did not affect early mating behavior. By contrast the olfactory stimuli became efficient when 2.5 micrograms EB treated females were given 10 micrograms progesterone (P) by the time of exposure to male urine. The results were discussed with respect to the role played by the olfactory system in the control of lordosis behavior throughout estrous cycle in female rats. P was concluded to be involved in the perception of the olfactory signals from the male which facilitate early mating behavior in diestrous female rats.

Hormonal control of the perception of the olfactory signals which facilitate lordosis behavior in the male rat

This study was designed to evaluate in the male rat the hormonal requirements for the facilitation of feminine behavior by the odor of male urine. Wistar rats from the WI and WII strains in our colony were orchidectomized (ORCH) as adults. A first group was given a single dose of 75 micrograms estradiol benzoate (EB) and tested for lordosis behavior 48 hr later. Exposure to the odor of male urine by 9 +/- 1 hr before the behavioral session did not increase the number of animals showing lordosis behavior as compared to non exposed controls. A second group of WI rats was given 0.5 micrograms EB every day for 4 to 8 days. A similar number of animals displayed lordosis behavior irrespective of whether they were exposed to the odor of urine before testing. A third group of WI rats was injected with 75 micrograms EB and 1 mg progesterone (P) 39 hr apart. Exposure to the odor of urine during estrogen treatment remained ineffective but significantly increased the number of animals showing lordosis behavior when performed at the time of P injection. A last group of WII rats was given 25 micrograms EB and 100 micrograms or 150 micrograms P 39 hr apart. Although uncapable as such to facilitate lordosis behavior the dose of 100 micrograms P rendered the animals responsive to the odor of urine. It was concluded that (1) the perception by feminized males of olfactory signals from the male was dependent on P; (2) an interaction between hormonal and sensory mechanisms was involved in the facilitation of lordosis behavior in the male rat.