The precise determination of the window of implantation significantly improves ART outcomes.

The human endometrium is receptive to the embryo for a specific period of time known as the window of implantation (WOI). During this period, the endometrium shows a specific gene expression profile suitable for endometrial function evaluation. ER Map is a molecular tool able to accurately predict endometrial receptivity status by transcriptomic analysis. In this retrospective study, including 2256 subfertile patients undergoing ART treatment, the clinical value of precise WOI determination is studied in detail. Results obtained when single embryo transfers (sET) were scheduled either within the WOI timeframe as established by ER Map, or deviating from this WOI, are assessed and compared. Data obtained showed that 34.18% (771/2256) of patients had a displaced WOI. Analysis of ART outcomes showed significantly higher pregnancy rates in transfers scheduled within the WOI predicted compared to transfers that deviated more than 12h from this WOI (44.35% vs 23.08%, p < 0.001). The deviation from the WOI had also an impact on the progression of pregnancy, with a significant increase in pregnancy loss (~ twofold) observed in transfers that deviated more than 12h from the WOI predicted. These results indicate that the precise determination of the WOI and personalised embryo transfer can significantly improve clinical outcomes.

Phase II randomised trial of chemoradiotherapy with FOLFOX4 or cisplatin plus fluorouracil in oesophageal cancer.

BACKGROUND: Concurrent chemoradiotherapy is a valuable treatment option for localised oesophageal cancer (EC), but improvement is still needed. A randomised phase II trial was initiated to assess the feasibility and efficacy in terms of the endoscopic complete response rate (ECRR) of radiotherapy with oxaliplatin, leucovorin and fluorouracil (FOLFOX4) or cisplatin/fluorouracil. METHODS: Patients with unresectable EC (any T, any N, M0 or M1a), or medically unfit for surgery, were randomly assigned to receive either six cycles (three concomitant and three post-radiotherapy) of FOLFOX4 (arm A) or four cycles (two concomitant and two post-radiotherapy) of cisplatin/fluorouracil (arm B) along with radiotherapy 50 Gy in both arms. Responses were reviewed by independent experts. RESULTS: A total of 97 patients were randomised (arm A/B, 53/44) and 95 were assessable. The majority had squamous cell carcinoma (82%; arm A/B, 42/38). Chemoradiotherapy was completed in 74 and 66%. The ECRR was 45 and 29% in arms A and B, respectively. Median times to progression were 15.2 and 9.2 months and the median overall survival was 22.7 and 15.1 months in arms A and B, respectively. CONCLUSION: Chemoradiotherapy with FOLFOX4, a well-tolerated and convenient combination with promising efficacy, is now being tested in a phase III trial.

Benefits of perineal colostomy on perineal morbidity after abdominoperineal resection.

PURPOSE: Abdominoperineal resection has a high rate of postoperative morbidity of the perineal wound. This study aimed to determine the effects of perineal colostomy on perineal morbidity after abdominoperineal resection. METHODS: All patients who underwent an abdominoperineal resection for rectal adenocarcinoma between 1993 and 2007 were studied. Two groups were identified and compared who had undergone either an iliac colostomy or a perineal colostomy. RESULTS: The analysis included 110 patients (iliac colostomy group, n = 41; perineal colostomy group, n = 69). There were fewer instances of pelviperineal morbidity (P = .008) and fewer instances of wound dehiscence (P = .02) in the perineal colostomy group, which resulted in a shorter time to healing (35.3 vs 45.1 d, respectively; P = .04). There was no specific postoperative morbidity in any patient and no difference between the 2 groups regarding long-term perineal morbidity. The benefits from perineal colostomy were statistically significant in patients who received radiation therapy in terms of pelviperineal morbidity (P = .01) and healing time (50.8 vs 35.9 days, respectively; P = .02), whereas no difference was found in patients who had not received radiation therapy. CONCLUSION: Perineal colostomy is a safe and functionally acceptable procedure for perineal reconstruction after abdominoperineal resection for rectal adenocarcinoma. In the present study, there was no additional morbidity related to perineal colostomy, and this procedure was associated with a decrease in perineal morbidity and healing time compared with primary perineal closure, in particular, after radiotherapy treatment.

Endonasal endoscopic oncologic resection and reconstruction of the anterior skull base in the elderly: A single-center retrospective study.

INTRODUCTION: In old and frail patients, oncologic anterior skull-base surgery through an endonasal endoscopic approach avoids the morbidity incurred by transfacial and transcranial approaches, sometimes considered unreasonable, although surgery remains the gold standard treatment for sinonasal cancer. OBJECTIVES: To assess the functional and oncologic results of this surgery in over-70 year-olds. MATERIAL AND METHODS: A single-center retrospective study included all patients aged over 70 years at surgery, who underwent endonasal endoscopic oncologic resection and reconstruction of the anterior skull base, between October 2008 and October 2018. RESULTS: Fifteen procedures in 13 patients met the inclusion criteria. Mean hospital stay was 7 days. All resections were considered R0, apart from one case with positive dura-mater margins (6.7%). All patients had complete radio-surgical treatment, in accordance with the REFCOR recommendations. Two cases of meningitis were reported (13.3%). At a median follow-up of 27 months, 4 patients presented local recurrence, 1 of whom also had lung metastases. Two patients died of disease-related or treatment-related causes. CONCLUSION: This technique is a feasible treatment in patients aged over 70 years, providing good functional results, and acceptable oncologic outcome.

Tolerance and efficacy of dose escalation using IMRT combined with chemotherapy for unresectable esophageal carcinoma: Long-term results of 51 patients.

PURPOSE: The optimal dose in esophageal cancer patients treated with definitive chemoradiation (CRT) remains debated. We herein report on the dosimetric results, treatment-related toxicities and long-term outcomes of escalated dose up to 60Gy delivered with intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: All consecutive patients that received a definitive CRT>50Gy for an unresectable esophageal carcinoma between 2010 and 2015 were retrospectively evaluated for this study. Methodology included data base search, delayed toxicity grading, statistical testing including frequency analysis and survival analysis. RESULTS: A total of 51 patients were irradiated for a squamous cell carcinoma (86.3%) or an adenocarcinoma (13.7%). The median age at diagnosis was 62 years. Seven patients were simultaneously irradiated for another synchronous primary tumor. Forty-six patients (90.2%) received concurrent platin-based chemotherapy. The median prescribed doses were 60Gy (54-66) and 48Gy (44.8-56) delivered in 30 (27-35) fractions to the high and the low risks PTV respectively. The mean dose delivered to the lungs was 11.4Gy (IC 95%: 4.8-19.8), the median volumes receiving up to 20Gy (V20) and 30Gy (V30) were 13.5% (3.0-46.0) and 4.6% (0.7-19.8) respectively. The mean dose delivered to the heart was 13.9Gy (IC 95%:0.3-31.3) with a median V40 of 3.3% (0.0-25.0). One treatment-related death occurred within days after RT completion (neutropenic aplasia). After a median follow-up of 2.7 years (95% CI: 1.9-4.3), the 2-year overall survival, disease free survival and loco-regional control rates were 53.6%, 42.0% and 72.8% respectively. Delayed treatment related-toxicities ≤grade 3 occurred among 25 patients (62.5%) mostly esophageal stricture (79.2%). CONCLUSION: We demonstrated in this study that dose escalation using IMRT in combination with platin-based chemotherapy as a definitive treatment for esophageal carcinoma is safe and results in higher loco-regional and control survival when compared to previously reported data.

G-protein-coupled receptor oligomers: two or more for what? Lessons from mGlu and GABAB receptors.

G-protein-coupled receptors (GPCRs) are key players in the precise tuning of intercellullar communication. In the brain, both major neurotransmitters, glutamate and GABA, act on specific GPCRs [the metabotropic glutamate (mGlu) and GABA(B) receptors] to modulate synaptic transmission. These receptors are encoded by the largest gene family, and have been found to associate into both homo- and hetero-oligomers, which increases the complexity of this cell communication system. Here we show that dimerization is required for mGlu and GABA(B) receptors to function, since the activation process requires a relative movement between the subunits to occur. We will also show that, in contrast to the mGlu receptors, which form strict dimers, the GABA(B) receptors assemble into larger complexes, both in transfected cells and in the brain, resulting in a decreased G-protein coupling efficacy. We propose that GABA(B) receptor oligomerization offers a way to increase the possibility of modulating receptor signalling and activity, allowing the same receptor protein to have specific properties in neurons at different locations.

[Definitive or neo-adjuvant chemoradiation in esophageal carcinoma?] / Cancer de l'œsophage : radio-chimiothérapie exclusive ou préopératoire ?

Management of resectable esophageal carcinoma is based on a multimodal treatment associating neo-adjuvant chemoradiation before surgery. This therapeutic sequence allows a disease-free survival rate at 2 years around 45% but remains associated with a high post-operative morbidity. In case of definitive chemoradiotherapy, the dose delivered to the macroscopic disease is a controversial topic since decades and the prognosis of patients treated in this setting at the dose of 50Gy remains poor. This article proposes a review of the main published data and the ongoing studies related to the management of these patients.

[Stereotactic hypofractionated radiation therapy as a bridge to transplantation for hepatocellular carcinoma: Case report of a complete pathological response and review of the literature]. / Place de la radiothérapie en conditions stéréotaxiques en traitement d'attente du carcinome hépatocellulaire avant transplantation hépatique : à propos d'un cas de réponse histologique complète sur explant et revue de la littérature.

Patients with hepatocellular carcinoma who are on liver transplant waiting list usually require local treatment to limit any risk of tumour growth. Historically percutaneous radiofrequency ablation or transarterial chemoembolization represented the major therapeutic alternatives. Depending on the size, or the topography of the lesion these two techniques may not be feasible. Radiation therapy under stereotactic conditions has recently emerged in the management of localized hepatocellular carcinoma as an alternative to the focused therapies performed to date. We herein report the case of a 43-year-old patient harbouring a complete histological response on explant after liver stereotactic irradiation and discuss its role in the management of hepatocellular carcinoma before liver transplantation.

[Changes in vertical HIV transmission: comparison between 1994 and 2004]. / Cambios en la transmisión vertical del virus de la inmunodeficiencia humana: comparación de los años 1994 y 2004.

BACKGROUND AND OBJECTIVE: Vertical transmission (VT) is the main route of human immunodeficiency virus (HIV) infection in children. Since the publication of PACTG 076 study in 1994, several preventive methods against the vertical transmission of the HIV have been developed. In this study, we compare the clinical and epidemiological profile of HIV-infected pregnant women and the VT rate in the years 1994 and 2004. PATIENTS AND METHOD: We looked at maternal, obstetric and pediatric variables of HIV-infected women and their children, born in 1994 and 2004, who were followed in Hospital La Paz. RESULTS: We included 40 mother-infant couples in 1994 and 35 couples in 2004. The HIV vertical transmission rate was 35% in 1994 and 0% in 2004. We did not find changes in Hepatitis C virus (HCV) vertical transmission. In 1994, HIV-infected mothers had a more advanced HIV-disease and the major route of HIV-transmission was the intravenous drug use. Vaginal delivery was more frequent and rupture of membranes was longer than in 2004. The main route of maternal HIV infection in 2004 was sexual contact. In this same year, the use of combination antiretroviral therapy, even during pregnancy, was generalized, the elective cesarean section was the most frequent form of delivery, and every newborn received zidovudine. CONCLUSIONS: In the last decade, there have been important epidemiological changes in HIV-infected mothers in our society. The administration of antiretroviral therapy during pregnancy and to the newborn, as well as other obstetric strategies, can prevent HIV vertical transmission. Nevertheless, we did not find any change in the risk of HCV vertical transmission.

[Systematic neck dissection in squamous cell carcinoma of the oral cavity]. / Evidement cervical systématique dans les cancers épidermoïdes de la cavité orale.

OBJECTIVES: To evaluate the neck control after prior surgical management of patients with squamous cell carcinoma of the oral cavity and to quantify the ratio of patients among whom neck dissection did not have a real therapeutic value. To discuss the usefulness of the sentinel node biopsy in this group of patients. METHOD: Retrospective analysis of patients with epidermoid carcinoma of the oral cavity who had systematically a neck dissection. RESULTS: Thirty-nine files of patients have been processed. We found 45% patients classified pN0 (among whom about one half where classified pT4). With a mean follow-up of 19 months, we did not find any cervical lymph node relapse. Five patients died (13.5%) without any cervical disease. CONCLUSION: The systematic cervical lymph node dissection remains the most effective means to obtain the neck control of squamous cell cancers of the oral cavity. It however was applied without therapeutic value for 45% of the patients of this series. The validation of the sentinel node concept as a method of cervical staging should make it possible to avoid this surgical procedure in more than one third of the cases.

Effects of the Physiological Age of Bananas on Their Susceptibility to Wound Anthracnose Due to Colletotrichum musae.

Wound anthracnose, caused by Colletotrichum musae, and early ripening are the main problems affecting the quality of export bananas (Musa AAA Cavendish) from the Caribbean. These problems generally concern bananas grown in lowland plantations during the rainy season. Three experiments were carried out to study the influence of the physiological age of bananas, calculated on the basis of mean daily temperature sums, on their susceptibility to anthracnose. Stressful growing conditions, especially soil flooding, slowed fruit growth but had no direct effect on fruit susceptibility to C. musae or on the green life. However, fruit that had accumulated lower temperature sums were less susceptible to wound anthracnose. By varying the source-sink ratio, we show that bananas of the same grade but different physiological ages had markedly different susceptibility to C. musae. Bananas with the same temperature sum accumulation but grown in different soil-climate conditions had different levels of susceptibility. Fruit grown in cooler, highland areas were less susceptible to C. musae than fruit of the same physiological age from lowland plantations. Our results suggest that temperature sum accumulation rate is a critical factor affecting the susceptibility of bananas to the pathogen.

[Postoperative external beam radiotherapy for medullary thyroid carcinoma with high risk of locoregional relapse]. / Radiothérapie postopératoire des carcinomes médullaires de la thyroïde à haut risque de rechute locorégionale.

PURPOSE: To assess the outcome of locally advanced medullary thyroid carcinoma treated with surgery and adjuvant external beam radiotherapy. PATIENTS AND METHODS: Twenty-nine consecutive patients with non-metastatic medullary thyroid carcinoma treated in our institution between January 1995 and December 2012 were retrospectively evaluated. All underwent curative-intended optimal surgery, followed by external beam radiotherapy because of high risk of locoregional relapse. Twelve patients were stage III, 16 IVa and 1 IVb. Positive surgical margins were present in 11 cases (10 R1 and 1 R2). Median and average preradiotherapy serum calcitonin were 141pg/mL and 699pg/mL, respectively. Fourteen patients received 3D-conformal radiotherapy and 15 received intensity-modulated radiotherapy. Median prescribed dose was 63Gy to the high-risk volumes and 54Gy to the low-risk volumes. Treatment was delivered in 30 fractions. The median gap between surgery and radiotherapy was 1.9months. Median follow-up was 76.4months. RESULTS: Kaplan-Meier estimates of 5-year locoregional relapse-free survival and overall survival were 79 and 96 %, respectively. Among the five locoregional relapses, two were related to a macroscopic metastatic cervical lymph node that was unfortunately not removed during the lymphadenectomy. Eight of ten patients with microscopic positive margins (R1) were controlled regarding the thyroidectomy bed. Eight patients had normal serum calcitonin after external beam radiotherapy, of whom only one developed a locoregional relapse during follow-up. Regarding the 21 patients with persistent positive serum calcitonin after treatment, only ten developed a macroscopic locoregional or distant relapse. One grade III and no grade IV acute morbidity were reported. Fifteen patients reported grade II chronic morbidity and no grade III/IV. CONCLUSION: Maximal surgery followed by adjuvant external beam radiotherapy as a treatment for locally advanced medullary thyroid carcinoma provides a high rate of long-term locoregional control and overall survival with limited toxicity. Postoperative external beam radiotherapy should be considered when patients present features indicating a high risk of locoregional relapse.

[Value of neck dissection before definitive radiation therapy for locoregionally advanced squamous cell carcinoma of the head and neck]. / Place du curage ganglionnaire avant radiothérapie exclusive dans la prise en charge des carcinomes épidermoïdes localement évolués des voies aérodigestives supérieures.

PURPOSE: Optimal timing of neck dissection remains debated in the conservative management of patients with locoregionally advanced squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: The files of 63 patients with radiographic evidence of bulky or necrotic nodal metastases treated by up-front neck dissection and definitive radiotherapy between 2000 and 2012 at two institutions were retrospectively reviewed. RESULTS: The primary site was oropharyngeal, hypopharyngeal or laryngeal in 63%, 21% and 13% cases, respectively. Overall, 83% of the tumours were staged pN2b or more. Extracapsular spread was found in 48 cases (77%). After a 48-month median follow-up, the 3-year locoregional control and overall survival were 88% and 68%, respectively. Only one isolated failure occurred in the dissected neck. CONCLUSION: This combination therapy provides a good locoregional tumour control. It should be considered as an option in laryngeal, hypopharyngeal or oropharyngeal squamous cell carcinomas with bulky or necrotic nodal metastases at presentation.

Toxicity and efficacy of cetuximab associated with several modalities of IMRT for locally advanced head and neck cancer.

PURPOSE: Intensity-modulated radiation therapy (IMRT) has shown its interest for head and neck cancer treatment. In parallel, cetuximab has demonstrated its superiority against exclusive radiotherapy. The objective of this study was to assess the acute toxicity, local control and overall survival of cetuximab associated with different IMRT modalities compared to platinum-based chemotherapy and IMRT in the ARTORL study (NCT02024035). PATIENTS AND METHOD: This prospective, multicenter study included patients with epidermoid or undifferentiated nasopharyngeal carcinoma, epidermoid carcinoma of oropharynx and oral cavity (T1-T4, M0, N0-N3). Acute toxicity, local control and overall survival were compared between groups (patients receiving cetuximab or not). Propensity score analysis at the ratio 1:1 was undertaken in an effort to adjust for potential bias between groups due to non-randomization. RESULTS: From the 180 patients included in the ARTORL study, 29 patients receiving cetuximab and 29 patients treated without cetuximab were matched for the analysis. Ten patients (34.5%) reported acute dermal toxicity of grade 3 in the cetuximab group versus three (10.3%) in the non-cetuximab group obtained after matching (P=0.0275). Cetuximab was not significantly associated with more grade 3 mucositis (P=0.2563). There were no significant differences in cutaneous or oral toxicity for patients treated with cetuximab between the different IMRT modalities (P=1.000 and P=0.5731, respectively). There was no significant difference in local relapse-free survival (P=0.0920) or overall survival (P=0.4575) between patients treated with or without cetuximab. CONCLUSION: Patients treated with cetuximab had more cutaneous toxicities, but oral toxicity was similar between groups. The different IMRT modalities did not induce different toxicity profiles.

[Propositions for the selection and the delineation of peritumoral microscopic disease volumes in oral cavity and oropharyngeal cancers (lymph nodes excluded)]. / Proposition de sélection et délimitation des volumes cibles microscopiques péritumoraux dans les cancers de la cavité buccale et de l'oropharynx (aires ganglionnaires exclues).

This article reviews the concept of selectivity in peritumoral microscopic disease to be included in the Clinical Target Volume (CTV) for elective treatment for oral cavity and oropharyngeal squamous cell carcinoma, using the local tumoral spread. The objective of the present article is to present a procedure for the delineation of the target volumes, required for an appropriate application of 3-DCRT and IMRT for head and neck cancers. These propositions are for the delineation of microscopic peritumoral target volumes when external beam irradiation is required. CTVs are illustrated on CT sections.

Concomitant radiochemotherapy or accelerated radiotherapy: analysis of two randomized trials of the French Head and Neck Cancer Group (GORTEC).

In the early 1990s, when conventional radiotherapy (RT) was the standard of care in patients with locally advanced head and neck squamous cell carcinoma (HNSCC), two main options were being tested to improve the efficacy and the therapeutic ratio of RT. The first approach evaluated the effect of adding chemotherapy (CT) simultaneously to RT (RT-CT), while the second approach assessed the effect of modified fractionated RT. To answer these two questions, in 1994, the French Group for Head and Neck Oncology Radiotherapy (GORTEC) initiated two randomized trials. A total of 494 patients were entered in these two parallel phase III multicenter trials comparing conventional RT (70 Gy in 35 fractions) either with concomitant RT-CT (226 patients; 70 Gy in 35 fractions with three cycles of a 4-day regimen comprising carboplatin and 5-fluorouracil [5FU]) or with very accelerated RT (268 patients) delivering 64 Gy in 3 weeks. The 5-year overall survival (OS), specific disease-free survival (DFS), and local-regional control rates were improved in favor of simultaneous RT-CT, whereas local-regional control was significantly improved with accelerated RT, along with a marginal effect on OS and DFS. This increased antitumor efficacy was in both cases associated with a marked increase in acute RT-induced toxicity, which was more pronounced with accelerated RT, whereas late effects were marginally increased with the addition of CT and not influenced by accelerated RT. We conclude that both concomitant RT-CT and accelerated RT improved tumor control rates, as compared to conventional RT, along with increased but manageable toxicity. The two regimens are currently being tested in an ongoing randomized study and also being compared to moderately accelerated RT and concomitant CT.

Platelet factor four and protamine sulfate neutralization of heparin fractionated according to anionic charge density.

The role of heparin structure in neutralization by the neutralizing substances (NS) platelet factor 4 (PF4) and protamine sulfate (PS) was investigated using a thrombin clotting assay and a series of more homogeneous heparin fractions varying systematically in charge density (Z). For a given heparin, plotting inverse clotting times measured without NS, and in the presence of PF4 or PS, vs heparin concentration yielded approximately parallel straight lines displaced horizontally according to the amount of NS. Potencies of heparin fractions in the absence of NS, or in the presence of PF4 of PS, depended almost identically upon Z2. Small but significant quantitative differences in potency among equivalent fractions from different heparins showed both PF4 and PS had a slight preference for the least active subfraction of decolorized heparins, but for the most active subfraction of undecolorized heparins. Neutralization of heparin by PF4 and PS probably proceeds by similar mechanisms, but the details of structure outside the antithrombin III-binding oligosaccharide of heparin may enter in differently.

The effectiveness of resource allocation methods used by RWCA Title II Consortia in Virginia.

The authors sought to determine the following: (1) How rigorous are the current resource allocation methods used by Virginia's five regional Ryan White CARE (Comprehensive AIDS Resources Emergency) Act Title II consortia? (2) How useful are existing databases in allocating resources? (3) Is it feasible to introduce a standardized performance measurement approach for state-level assessment of consortia effectiveness? The authors reviewed proposals and progress reports from each of the consortia to the Virginia public health agency; they then visited each of the consortia to solicit information to refine the study questions and to review the consortia's databases. The authors reviewed the literature on existing models used to allocate resources, and surveyed members of the Virginia consortia about how they used various resource allocation tools, how effective these tools were, and how ready the consortia were to be evaluated regarding resource allocation. The authors found no uniform process for the allocation of Title II funds in Virginia. Consortia members who felt connected and involved with their consortium were significantly more knowledgeable about its operations and more likely to consider it effective. A consortium's use of a continuous quality improvement (CQI) approach to allocating resources was strongly associated with its members' perception that the consortium was effective. Statewide performance and/or outcome measures cannot be set without some standardized expectations for performance. To do this, some expectations for basic resource allocation procedures must be established. Three of Virginia's five consortia will make use of this study's instrumentation in their next resource allocation processes, and, if their experiences are useful, a statewide process may be established. If a statewide process is established, regional consortia must continue to be able to determine local needs and to respond with locally appropriate service planning.

The atypical antidepressant and neurorestorative agent tianeptine is a µ-opioid receptor agonist.

Current pharmacological treatments of depression and related disorders suffer from major problems, such as a low rate of response, slow onset of therapeutic effects, loss of efficacy over time and serious side effects. Therefore, there is an urgent need to explore new therapeutic approaches that address these issues. Interestingly, the atypical antidepressant tianeptine already meets in part these clinical goals. However, in spite of three decades of basic and clinical investigations, the molecular target of tianeptine, as well as its mechanism of action, remains elusive. Herein, we report the characterization of tianeptine as a µ-opioid receptor (MOR) agonist. Using radioligand binding and cell-based functional assays, including bioluminescence resonance energy transfer-based assays for G-protein activation and cAMP accumulation, we identified tianeptine as an efficacious MOR agonist (K(i Human) of 383±183 nM and EC(50 Human) of 194±70 nM and EC(50 Mouse) of 641±120 nM for G-protein activation). Tianeptine was also a full δ-opioid receptor (DOR) agonist, although with much lower potency (EC(50 Human) of 37.4±11.2 µM and EC(50 Mouse) of 14.5±6.6 µM for G-protein activation). In contrast, tianeptine was inactive at the κ-opioid receptor (KOR, both human and rat). On the basis of these pharmacological data, we propose that activation of MOR (or dual activation of MOR and DOR) could be the initial molecular event responsible for triggering many of the known acute and chronic effects of this agent, including its antidepressant and anxiolytic actions.