Cardiorespiratory responses to submaximal incremental exercise are not affected by one night's sleep deprivation during the follicular and luteal phases of the menstrual cycle

The purpose of the study was to investigate the effects of one night's sleep deprivation on the cardiorespiratory responses to exercise during the follicular and luteal phases of the menstrual cycle. We have studied nine, healthy females aged 24-35 years with regular menstrual cycles. Each subject performed spirometric tests at rest and then an incremental exercise testing during 11-13 days of follicular phase and 22-24 days of luteal phase following one normal night's sleep or one night's sleep loss. Compared with resting values exercise produced significant increases in cardiorespiratory variables including oxygen uptake (VO2), carbon dioxide production (VCO2), tidal volume (VT), respiratory rate (RR), minute ventilation (VE), systolic blood pressure, heart rate (HR) and respiratory quotient (R). However, it did not alter significantly diastolic blood pressure, end-tidal PO2 (PETO2), end-tidal PCO2 (PETCO2) and arterial oxygen saturation (SaO2). Spirometric variables which include forced vital capacity (FVC), forced expiratory volume in one s (FEV1), FEV1/FVC%, forced expiratory volume in three s (FEV3), forced expired flow from 25-75% of FVC (FEF 25-75%), forced expired flow at 25% of FVC (FEF 25%), forced expired flow at 50% of FVC (FEF 50%), forced expired flow at 75% of FVC (FEF 75%), forced expired flow from 75-85% of FVC (FEF 75-85%), peak expiratory flow (PEF), expiratory reserve volume (ERV), inspiratory capacity (IC) and maximal voluntary ventilation (MVV) and cardiorespiratory variables were not different between the cycle phases after one normal night's sleep or one night's sleep deprivation. Neither menstrual cycle phase nor sleep deprivation affected spirometric and cardiorespiratory parameters. We suggest that one night's sleep deprivation does not produce alterations in spirometric parameters and cardiorespiratory responses to submaximal incremental exercise during the follicular and luteal phases.     

Effects of the menstrual cycle on timing and depth of breathing at rest

Volume and timing components of resting ventilation were measured serially in 40 women aged 18 to 36 yr, during menstrual, follicular and luteal phases of menstrual cycle. Resting minute ventilation (VE) was significantly higher (P < 0.001) in luteal phase than in menstrual and follicular phases; in the two latter phases VE was almost equal. This increment in VE during the luteal phase was due to a significant rise (P < 0.001) in tidal volume (VT). Respiratory frequency (f) was unchanged throughout the cycle. Although there was a mean increases in inspiratory time (T1) during the luteal phase compared to the other two phases, the difference did not reach statistical significance. Duty cycle, T1/Ttot, was also unchanged throughout menstrual cycle. However, mean inspiratory flow, VT/T1, was significantly higher (P < 0.05 and P < 0.01) during luteal phase as compared to that during menstrual or follicular phases respectively. Pulmonary mechanics, as measured by forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced mid expiratory flow rate (FEF25%, 75%), were within normal limits and remained unaltered during the menstrual cycle. Therefore, in the absence of alteration of pulmonary mechanics, the luteal increase in ventilation and inspiratory flow suggests a possible role for progesterone in stimulating the respiratory drive, either centrally or through the peripheral chemoreceptors or by both.     

Effect of oral contraceptives on respiratory function

The present study was carried out to assess the lung functions in oral contraceptive administered women. Lung function tests were carried out with Spirometer (Vitallograph Compact II). A significant increase in vital capacity (VC) was observed in these women as compared to normal control. There was also a significant decrease in forced expiratory volume in 1 sec./vital capacity (FEV1/VC%) and forced expiratory volume in 1 sec./forced vital capacity (FEV1/FVC%) among oral contraceptive administered women as compared to controls. Further, a significant increase in peak expiratory flow rate (PEF), reduction in forced expiratory flow rate (FEF75-85%) and FEF75% were observed among oral contraceptive administered women as compared to controls. The increase in VC and PEF might be due to the synthetic form of progesterone (progestins) present in oral contraceptive pills which causes hyperventilatory changes. Synthetic progesterone during luteal phase of menstrual cycle might increase the static and dynamic volumes of lung i.e. VC and PEF. But FEF75% showed a decrease which might be due to the lower neuromuscular coordination during breathing.     

The influence of menstrual cycle phase on sensitivity to ethanol-like discriminative stimulus effects of GABA(A)-positive modulators.

Previous studies showed that sensitivity to the ethanol-like discriminative stimulus effects of allopregnanolone and ethanol are enhanced during the luteal phase of the menstrual cycle when progesterone levels peak in monkeys trained to discriminate 1.0 g/kg ethanol. The present study further explored the influence of the menstrual cycle phase on the discriminative stimulus effects of ethanol, allopregnanolone, and midazolam. Female adult cynomolgus monkeys (Macaca fascicularis) were trained to discriminate 1.0 g/kg ethanol (n = 3) or 2.0 g/kg ethanol (n = 4) (20% w/v; i.g.) from water (i.g.). A cumulative dosing procedure was used to test discriminative stimulus effects of ethanol (0.5-2.5 g/kg; i.g.) and the ethanol-like discriminative stimulus effects of allopregnanolone (0.1-1.0 mg/kg; i.v.) or midazolam (1.0-17 mg/kg; i.g.) during the follicular vs. luteal phase of the menstrual cycle. In the 2.0-g/kg group, sensitivity to the ethanol-like effects of allopregnanolone was increased during the luteal vs. follicular phase in two of three monkeys. In contrast, average sensitivity to ethanol was not different in the luteal compared to the follicular phase in the 2.0-g/kg group. Finally, there was no difference in sensitivity to midazolam between the follicular and luteal phases in monkeys trained with either 2.0 g/kg or 1.0 g/kg ethanol. Overall, the ethanol-like discriminative stimulus effects of midazolam are not sensitive to the menstrual cycle phase. In addition, there was less influence of the menstrual cycle phase on allopregnanolone and ethanol sensitivity in a 2.0-g/kg compared to a 1.0-g/kg ethanol training dose.     

Prediction equation for lung functions in South Indian children

Lung functions including VC, IVC, FVC, FEV0.5, FEV1, PEF, FEF0.2-1.2, FEF25-75%, FEF75-85%, PIF, FMFT, MVV(IND), peak expiratory flow at 25%, 50% and 75% of FVC, peak inspiratory flow at 75%, 50%, 25% and the ratio between different lung volumes were measured with Vitallograph Compact-II spirometer on 109 South Indian school boys in the age group of five to sixteen years. The results show an increase in "lung volumes" and "flow rates" with increase in age, height and weight. FMFT and MVV(IND) also increase with increase in anthropometric measurements. All the lung functions except FEF75-85% and the ratio between different lung volumes show significant positive correlation with age, height and weight. Regression equations were derived for predicting normal lung functions for healthy South Indian boys. Lung volumes and flow rates were lower than North Indian and foreign boys. The decrease in lung functions in South Indian boys were due to their sea level dwelling, dietary habits and comparatively lower anthropometric measurements.     

Luteal-phase accentuation of acoustic startle response in women with premenstrual dysphoric disorder.

Alterations in central nervous system response to menstrual cycle-related fluctuations in neuroactive steroids are thought to underlie the emergence of negative affect in the luteal phase of the menstrual cycle in women with premenstrual dysphoric disorder (PMDD). Such changes in the neuroendocrine milieu may lead to heightened arousal and response to stress in women with PMDD. Using the acoustic startle paradigm, we sought to determine whether women with PMDD have an accentuated physiologic response to a mildly aversive stimulus during the luteal compared to follicular phase. Further, we also examined the impact of visual affective stimuli on acoustic startle response (ASR) magnitude. During the follicular and luteal phases of the menstrual cycle, acoustic stimuli (103 dB) were delivered to 15 women with PMDD and 14 healthy menstruating women of similar age. After obtaining baseline ASR, the procedure was repeated when subjects viewed pleasant, neutral and unpleasant pictures. There was a significant group by menstrual cycle phase interaction for baseline ASR magnitude, which can be attributed to the heightened startle magnitude in women with PMDD compared to healthy women during the luteal relative to the follicular phase. The direction and degree to which picture viewing modulated the startle magnitude did not vary by group or menstrual cycle phase. These data suggest that menstrual cycle phase has a powerful modulatory effect on physiologic reactivity in women with PMDD but not in healthy women. Physiologic response to affective stimuli appears to be intact in women with PMDD across the menstrual cycle.     

普通肺炎支原体肺炎患儿肺功能检测的临床意义

目的：探讨儿童普通肺炎支原体肺炎（MPP）急性期及恢复期肺通气功能的变化及其检测意义。方法：选取2014年6月至2015年6月在我院住院的5~14岁普通MPP急性期（发病1周内）患儿74例,行常规肺功能检测,随访至恢复期（发病后第3周）,66例再次行常规肺功能检测;另选取同期健康儿童60例作为对照组。结果：普通MPP急性期各项肺功能指标（FVC、FEV1、PEF、FEF25、FEF50、FEF75、MMEF）与FEV1/FCV较恢复期均下降（P均<0.01）;恢复期FVC、FEV1、PEF基本恢复正常,而FEF25、FEF50、FEF75、MMEF较对照组仍有减低（P均<0.01）;急性期与恢复期FEV1/FVC均保持在正常范围。结论：儿童普通MPP急性期存在限制性、阻塞性通气功能障碍及小气道损害,限制性通气功能障碍相对较轻,小气道损害相对较重,而在恢复期限制性及阻塞性肺通气功能障碍明显改善,但仍有小气道损害,故普通MPP小气道损害时间明显较大气道长。肺通气功能检测可以较为客观地反映肺损害的情况,可以判断病情轻重、评估疗效及判断预后。     

Effect of advanced uncomplicated pregnancy on pulmonary function parameters of North Indian subjects

The study was conducted on 100 pregnant women in third trimester of uncomplicated pregnancy (Test group) and 100 age-matched non-pregnant women (Control group) in the age group of 25 to 35 years. Pulmonary function test parameters FVC, FEV1, PEFR and FEF25-75% recorded using Medspiror. The FEV1/FVC ratio was calculated. All parameters except FEV1/ FVC ratio were found to decline in the Test group as compared to the Control group. The decrease in FEV1 with pregnancy was not of such amplitude as decrease in FVC, and hence FEV1/FVC ratio was seen to increase. This study validates the physiological changes in pulmonary function brought by pregnancy and highlights the need to compile expected and accepted alterations in predicted values of PFT in comparison with the non gravid states for safer outcome of the pregnancy.     

小气道功能指标在儿童哮喘病情严重程度评估及临床诊断中的应用

目的 探讨小气道功能指标在儿童哮喘病情严重程度评估及临床诊断中的应用价值。方法 选取2013年5月至2016年4月于郑州市第二人民医院56例哮喘急性发作期病儿作为哮喘组,并根据哮喘急性发作严重程度分为轻度(21例)、中度(20例)和重度(15例)三个亚组,同时选取同期、年龄相仿及性别相匹配的30例因其他原因引起喘息咳嗽的慢性炎症病儿和32例入院检查健康儿童分别作为非哮喘组和对照组,收集各组儿童一般资料,采用肺功能测定系统检测各组儿童用力肺活量(FVC)、最大呼气流量(PEF)、第1秒用力呼气容积(FEV1)和FEV1/FVC比值、呼出25%肺活量时呼气流速(FEF25%)、呼出50%肺活量时呼气流速(FEF50%)、呼出75%肺活量时呼气流速(FEF75%)、最大中期呼气流速(MMEF)等指标。结果 与对照组比较,非哮喘组和哮喘组病儿FVC、FEV1、PEF、FEF25%、FEF50%、FEF75%和MMEF等指标均显著降低(P<0.05),且哮喘组病儿上述指标显著低于非哮喘组[(1.42±0.36)L比(1.85±0.47)L、(1.25±0.32)L比(1.42±0.41)L、(2.68±0.64)L比(3.25±0.77)L/s、(2.54±0.65)L/s比(3.74±0.68)L/s、(1.58±0.36)L/s比(2.24±0.71)L/s、(0.61±0.37)L/s比(1.02±0.41)L/s、(1.42±0.49)L/s比(1.89±0.68)L/s)](均P<0.05),而三组病儿FEV1/FVC指标差异无统计学意义(P>0.05)。哮喘急性发作期不同程度病儿用力呼出25%肺活量的呼气流量占预计值百分比(FEF25pred%)、用力呼出50%肺活量的呼气流量占预计值百分比(FEF50pred%)、用力呼出75%肺活量的呼气流量占预计值百分比(FEF75pred%)、最大呼气中期流量占预计值的百分比(MMEFpred%)等指标比较差异有统计学意义(P<0.05),且随着病情程度增加,病儿FEF25pred%、FEF50pred%、FEF75pred%、MMEFpred%等指标呈现明显降低趋势(P<0.05),FEF25%和FEF75%指标在不同严重程度哮喘病儿中异常率比较,差异有统计学意义(P<0.05),FEF50%和MMEF指标比较差异无统计学意义(P>0.05),其中FEF25%主要表现为轻度异常,而FEF75%主要表现为重度异常。结论 小气道功能指标在儿童哮喘病情严重程度评估及临床诊断具有重要意义,随着病情加剧,小气道功能指标明显降低,且异常率显著增加。     

Response to alcohol in women: role of the menstrual cycle and a family history of alcoholism

The present study determined whether: (1) the response to alcohol varied as a function of menstrual cycle phase and (2) women with a paternal history of alcoholism (FHP) were less sensitive to the effects of alcohol compared to women without a family history of alcoholism (FHN). The behavioral effects of alcohol (0.00, 0.25, and 0.75 g/kg) were evaluated in 21 FHN and 24 FHP women; each dose was tested during both the midfollicular and late luteal phases of the menstrual cycle. Baseline negative mood was increased during the luteal phase compared to the follicular phase (increased Beck Depression scores and decreased Vigor, Arousal, and Friendly scores). Alcohol increased ratings of Drug Liking and Good Drug Effect more in the luteal phase than the follicular phase. FHP women had greater negative mood during the luteal phase and some of these dysphoric effects were increased by alcohol more in FHP women than FHN women. Alcohol impaired performance, with no group or menstrual cycle differences. However, consistent with previous studies, FHP women were less impaired by alcohol than FHN women on the balance task. These data indicate that (1) the differences in response to alcohol across the menstrual cycle are subtle, although alcohol is liked more during the luteal phase; (2) increases in dysphoric mood during the luteal phase are more pronounced in FHP women compared to FHN women, particularly after alcohol; and (3) the differences observed in response to alcohol between FHP and FHN women are less pronounced than previously shown in men.     

Comparative pharmacokinetics of paracetamol in men and women considering follicular and luteal phases

The pharmacokinetics of paracetamol administered in a single dose were investigated and compared in young male and female subjects, considering follicular and luteal phase of the menstrual cycle. The mean AUC for paracetamol in the blood of female subjects was significantly increased by 39% and 51%, respectively, taking into account the follicular and luteal phase, in comparison with the AUCs of male volunteers. The peak plasma concentration revealed significantly higher values in women in both phases, by 48% and 66%, respectively. The time to reach the peak concentration was shorter by 8% in follicular phase than in males. The difference was statistically insignificant. Elimination constant decreased in follicular phase by 15% and in luteal phase by 21% in comparison with males (the difference--statistically insignificant). The paracetamol half-life was longer (although not significantly) in women than in men: in follicular phase by 29 min, i.e. 15%, and in luteal phase by 65 min, i.e. 33%. The apparent volume of distribution was found to be significantly lower in the female group by 35% and 40% in follicular and luteal phase, respectively. Comparing data obtained in the follicular and luteal phase, it was shown that the AUC was larger, peak plasma concentration was higher and biological half-life was longer in luteal phase. It is likely that the differences in some pharmacokinetic parameters between men and women, as well as in women considering both phases of menstrual cycle, might be of clinical significance.     

重叠综合征夜间低氧与肺功能相关性的临床研究

目的观察重叠综合征患者夜间呼吸紊乱、低氧情况及肺功能的改变,探讨重叠综合征的发病机制。方法对42例重叠综合征、30例COPD患者进行PSG监测,并行肺功能检查,记录AHI、Lapnea、LSaO2、SaO2<90%时间及FEV1、FEV1/FVC、FEF50%、FEF25%。结果重叠综合征患者BMI、AHI、Lapnea、SaO2<90%时间较单纯COPD患者明显增加;LSaO2及FEV1、FEV1/FVC、FEF50%、FEF25%较单纯COPD患者明显下降;重叠综合征患者FEV1/FVC、FEF50%、FEF25%与AHI、SaO2<90%时间呈负相关,与LSaO2呈正相关。结论重叠综合征患者较单纯COPD患者夜间低氧明显;夜间低氧原因除了上气道阻力增加外,COPD本身引起肺功能不完全可逆性改变也占主要的作用;同时睡眠呼吸紊乱亦可加重肺功能损害。     

An epidemiological study of pulmonary function tests in geriatric population of central India

We have studied Pulmonary Function Tests (PFTs) namely Vital Capacity (VC). Forced Vital Capacity (FVC), and Forced Expiratory Volume in First Second (FEV1). Forced Expiratory Flow(FEF 25-50%) in 1200 elderly subjects above 60 years of age of which 570 were females and 630 males. Mean age was 69.22 +/- 5.57 years in males and 68.77 +/- 5.44 in females. The mean value of ventilatory parameters were as follows-1) VC 2.99 +/- 0.5 lt in males and 1.89 +/- 0.29 lt in females. 2) FVC 2.69 +/- 0.58 lt. in males and 1.76 +/- 0.21 lt in females. 3) FEV1/FVC% 83.82 +/- 10.62% in males and 83.37 +/- 11.93% in females. 4) FEF 25-75% was 2.81 +/- 1.20 lt/sec in males and 2.13 +/- 1.27 lt/sec. Physical as well as ventilatory parameters were less in females than for males. The correlation of age with VC and FEV1 was highly significant (P < 0.01) but with FVC was not significant (P > 0.05). The correlation of height, weight and body surface area was not significant with any ventilatory parameter (P > 0.05). Multiple regression equations for VC, FVC and FEV1 were formulated for males and females taking height and age as variables. The predicted values correlated excellently with observed values.     

5α-Reductase Inhibition Prevents the Luteal Phase Increase in Plasma Allopregnanolone Levels and Mitigates Symptoms in Women with Premenstrual Dysphoric Disorder

Changes in neurosteroid levels during the luteal phase of the menstrual cycle may precipitate affective symptoms. To test this hypothesis, we stabilized neurosteroid levels by administering the 5α-reductase inhibitor dutasteride to block conversion of progesterone to its neurosteroid metabolite allopregnanolone in women with premenstrual dysphoric disorder (PMDD) and in asymptomatic control women. Sixteen women with prospectively confirmed PMDD and 16 control women participated in one of two separate randomized, double-blind, placebo-controlled, cross-over trials, each lasting three menstrual cycles. After one menstrual cycle of single-blind placebo, participants were randomized to receive, for the next two menstrual cycles, either double-blind placebo or dutasteride (low-dose 0.5 mg/day in the first eight PMDD and eight control women or high-dose 2.5 mg/day in the second group of women). All women completed the daily rating form (DRF) and were evaluated in clinic during the follicular and luteal phases of each menstrual cycle. Main outcome measures were the DRF symptoms of irritability, sadness, and anxiety. Analyses were performed with SAS PROC MIXED. In the low-dose group, no significant effect of dutasteride on PMDD symptoms was observed compared with placebo (ie, symptom cyclicity maintained), and plasma allopregnanolone levels increased in women with PMDD from follicular to the luteal phases, suggesting the absence of effect of the low-dose dutasteride on 5α-reductase. In contrast, the high-dose group experienced a statistically significant reduction in several core PMDD symptoms (ie, irritability, sadness, anxiety, food cravings, and bloating) on dutasteride compared with placebo. Dutasteride had no effect on mood in controls. Stabilization of allopregnanolone levels from the follicular to the luteal phase of the menstrual cycle by blocking the conversion of progesterone to its 5α-reduced neurosteroid metabolite mitigates symptoms in PMDD. These data provide preliminary support for the pathophysiologic relevance of neurosteroids in this condition.     

Pulmonary functions in workers of fertiliser and chemical industry

The present study was undertaken to assess the pulmonary functions in fertiliser and chemical industry workers of Kerala. Pulmonary function test was performed with Vitalograph Compact-II spirometer. Exposure to different chemicals, noxious gases and particulate matter of fertiliser and chemical industry was injurious to the normal pulmonary function. Significant decline in lung volumes, viz. FVC, FEV1, FEV1/FVC% (P < 0.01) and flow rates, viz. FEF25-75%, FEF0.2-1.2, FEF25%, FEF50%, FEF75% (P < 0.01) among non-smokers and smokers than that of normal controls was observed. The findings of this study also suggest that with increased duration of exposure to industrial pollutants, lung volumes and flow rates were significantly reduced in workers.     

Salt preference across different phases of menstrual cycle

It is well established that women experience food craving for particular foods and gain weight in relation to phases of menstrual cycle. In this study, the preference for different concentrations of salt sprayed on bland popcorn was assessed in 55 healthy women (age 18 to 22 yrs). Salt solutions of 0, 1, 2, 3 and +3 molar strength were used. Samples of sprayed popcorn were consumed in random order and preference marked on a Likert scale. It was observed that women preferred unsalted popcorn in the menstrual phase more than in the luteal phase. The preference for salted popcorn was most during the luteal phase and was proportionate to the strength of the salt solution used. Statistical analysis revealed significant differences in the preference rating between the menstrual phase and the other two phases. There was no significant difference in preference between the luteal and follicular phases.     

Effects of oral contraceptives on plasma neutral amino acids and cholesterol during a menstrual cycle

Objective: Concentrations of plasma neutral amino acids, i.e. threonine, serine, asparagine, glycine, alanine, citrulline, α-aminobutyric acid, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, and tryptophan, and serum cholesterol, were determined at the follicular (Day 4), mid-cycle (Day 16) and luteal (Day 25) phases of the menstrual cycle in 15 users of the new generation of combined oral contraceptives (OC), 11 on multiphase combined OC, and 17 controls. Results: The controls showed a decrease in the sum of amino acids to 95% at mid-cycle and 90% in the luteal phase relative to the follicular phase, and a significant decrease in the tyrosine level at the luteal relative to the follicular phase. Since there was no significant difference between the two OC subgroups in the levels of the specified variables at either of the phases, the two groups were considered together. The sum of amino acids in the OC group decreased to 89% at mid-cycle and 91% at the luteal phase relative to the follicular phase, indicating less metabolic effect than reported for older OC formulations. Compared to the controls, the OC group showed significant increased threonine level at the luteal phase, decreased glycine levels at mid-cycle and the luteal phases, decreased citrulline level at mid-cycle, and markedly decreased tyrosine levels at the mid-cycle and luteal phases. Neither total nor high density lipoprotein (HDL) cholesterol differed significantly between the control and OC groups. Conclusion: The results suggest that the metabolic effects of the new generation combined OC on neutral amino acids and cholesterol are only modest to slight, except for the effect on tyrosine, the brain noradrenaline precursor, which may cause disturbances of various noradrenaline-mediated central functions in susceptible subjects.     

Hexachlorobenzene (HCB) suppresses circulating progesterone concentrations during the luteal phase in the cynomolgus monkey.

Hexachlorobenzene (HCB) is a known reproductive toxin. However, the full spectrum of its reproductive toxicity is unknown. Consequently, the effect of HCB on serum oestradiol (E2) and progesterone (P4) concentrations during the follicular (days 1-9), periovulatory (days 10-14) and luteal (days 15 to beginning of next menses) phases was investigated in the spontaneously cycling cynomolgus monkey. Adult female cynomolgus monkeys (n = 16) were randomly assigned to one of four treatment groups and orally doses with gelatin capsules containing HCB (0.0, 0.1, 1.0 and 10.0 mg kg-1 body wt. day-1) mixed with glucose. A 10-week acclimitization phase was followed by 13 weeks of dosing. HCB induced a dose-dependent suppression of serum P4 concentrations during the luteal phase. However, circulating levels of P4 were unaffected during the follicular and periovulatory phases of the menstrual cycle. Serum E2 concentrations, body weight, menstrual cycle length and duration of menses were not affected by HCB treatment. The range of menstrual cycle length and duration range of menses, however, were broader in the highest dose group. We conclude that HCB interfers with mechanisms regulating ovarian steroidogenesis and suppresses P4 levels during the luteal phase in the cynomolgus monkey.     

Sex and menstrual cycle effects on progressive ratio measures of cocaine self-administration in cynomolgus monkeys.

Fluctuations in ovarian steroid hormones across the menstrual/estrous cycle influence the abuse-related effects of acute cocaine administration in women and chronic cocaine self-administration in rodents, but there have been no comparable studies in non-human primates. The interactions among sex, menstrual cycle phase, and cocaine self-administration (0.0032, 0.01, and 0.032 mg/kg/injection (inj)) under a progressive ratio schedule were investigated in four female and two male cynomolgus monkeys. Females were given unrestricted access to cocaine across 54 menstrual cycles, and males were studied over 23 pseudo-cycles of 30 days duration. Ovulatory cycles were defined by luteal phase elevations in progesterone and 44 cycles were ovulatory. During ovulatory menstrual cycles, females reached significantly higher progressive ratio break points than males at all three unit doses of cocaine (P<0.001). During anovulatory cycles, females also reached significantly higher break points than males for 0.032 mg/kg/inj cocaine (P<0.01). Progressive ratio break points for cocaine (0.01 and 0.032 mg/kg/inj) did not vary significantly as a function of ovarian steroid hormone levels during the follicular and the luteal phase of ovulatory menstrual cycles, or during anovulatory cycles. Progressive ratio break points for 0.0032 mg/kg/inj cocaine were significantly higher during the follicular phase than during the late luteal phase (P<0.05-0.001). There were no systematic changes in progressive ratio break points in male pseudo-cycles. Significant cocaine dose-related sex differences were observed, but no consistent changes in cocaine self-administration as a function of menstrual cycle phase, or levels of estradiol and progesterone, were detected in female cynomolgus monkeys.     

Increased impulsive choice for saccharin during PCP withdrawal in female monkeys: influence of menstrual cycle phase

Background

In previous studies with male and female rhesus monkeys, withdrawal of access to oral phencyclidine (PCP) self-administration reduced responding for food under a high fixed-ratio (FR) schedule more in males than females, and with a delay discounting (DD) task with saccharin (SACC) as the reinforcer impulsive choice for SACC increased during PCP withdrawal more in males than females.

Objectives

The goal of the present study was to examine the effect of PCP (0.25 or 0.5 mg/ml) withdrawal on impulsive choice for SACC in females during the follicular and luteal phases of the menstrual cycle.

Materials and methods

In component 1, PCP and water were available from two drinking spouts for 1.5 h sessions under concurrent FR 16 schedules. In component 2, a SACC solution was available for 45 min under a DD schedule. Monkeys had a choice of one immediate SACC delivery (0.6 ml) or six delayed SACC deliveries, and the delay was increased by 1 s after a response on the delayed lever and decreased by 1 s after a response on the immediate lever. There was then a 10-day water substitution phase, or PCP withdrawal, that occurred during the mid-follicular phase (days 7–11) or the late luteal phase (days 24–28) of the menstrual cycle. Access to PCP and concurrent water was then restored, and the PCP withdrawal procedure was repeated over several follicular and luteal menstrual phases.

Results

PCP deliveries were higher during the luteal (vs follicular) phase. Impulsive choice was greater during the luteal (vs follicular) phase during withdrawal of the higher PCP concentration.

Conclusions

PCP withdrawal was associated with elevated impulsive choice for SACC, especially in the luteal (vs follicular) phase of the menstrual cycle in female monkeys.