Therapeutic Potential of Melatonin Counteracting Chemotherapy-Induced Toxicity in Breast Cancer Patients: A Systematic Review.

The purpose of this systematic review is to provide an overview of the existing knowledge on the therapeutic potential of melatonin to counteract the undesirable effects of chemotherapy in breast cancer patients. To this aim, we summarized and critically reviewed preclinical- and clinical-related evidence according to the PRISMA guidelines. Additionally, we developed an extrapolation of melatonin doses in animal studies to the human equivalent doses (HEDs) for randomized clinical trials (RCTs) with breast cancer patients. For the revision, 341 primary records were screened, which were reduced to 8 selected RCTs that met the inclusion criteria. We assembled the evidence drawn from these studies by analyzing the remaining gaps and treatment efficacy and suggested future translational research and clinical trials. Overall, the selected RCTs allow us to conclude that melatonin combined with standard chemotherapy lines would derive, at least, a better quality of life for breast cancer patients. Moreover, regular doses of 20 mg/day seemed to increase partial response and 1-year survival rates. Accordingly, this systematic review leads us to draw attention to the need for more RCTs to provide a comprehensive view of the promising actions of melatonin in breast cancer and, given the safety profile of this molecule, adequate translational doses should be established in further RCTs.

Potential of melatonin to reverse epigenetic aberrations in oral cancer: new findings.

It is now an accepted principle that epigenetic alterations cause cellular dyshomeostasis and functional changes, both of which are essential for the initiation and completion of the tumor cycle. Oral carcinogenesis is no exception in this regard, as most of the tumors in the different subsites of the oral cavity arise from the cross-reaction between (epi)genetic inheritance and the huge challenge of environmental stressors. Currently, the biochemical machinery is put at the service of the tumor program, halting the cell cycle, triggering uncontrolled proliferation, driving angiogenesis and resistance to apoptosis, until the archetypes of the tumor phenotype are reached. Melatonin has the ability to dynamically affect the epigenetic code. It has become accepted that melatonin can reverse (epi)genetic aberrations present in oral and other cancers, suggesting the possibility of enhancing the oncostatic capacity of standard multimodal treatments by incorporating this indolamine as an adjuvant. First steps in this direction confirm the potential of melatonin as a countermeasure to mitigate the detrimental side effects of conventional first-line radiochemotherapy. This single effect could produce synergies of extraordinary clinical importance, allowing doses to be increased and treatments not to be interrupted, ultimately improving patients' quality of life and prognosis. Motivated by the urgency of improving the medical management of oral cancer, many authors advocate moving from in vitro and preclinical research, where the bulk of melatonin cancer research is concentrated, to systematic randomized clinical trials on large cohorts. Recognizing the challenge to improve the clinical management of cancer, our motivation is to encourage comprehensive and robust research to reveal the clinical potential of melatonin in oral cancer control. To improve the outcome and quality of life of patients with oral cancer, here we provide the latest evidence of the oncolytic activity that melatonin can achieve by manipulating epigenetic patterns in oronasopharyngeal tissue.

The Coronavirus Disease 2019 (COVID-19): Key Emphasis on Melatonin Safety and Therapeutic Efficacy.

Viral infections constitute a tectonic convulsion in the normophysiology of the hosts. The current coronavirus disease 2019 (COVID-19) pandemic is not an exception, and therefore the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, like any other invading microbe, enacts a generalized immune response once the virus contacts the body. Melatonin is a systemic dealer that does not overlook any homeostasis disturbance, which consequently brings into play its cooperative triad, antioxidant, anti-inflammatory, and immune-stimulant backbone, to stop the infective cycle of SARS-CoV-2 or any other endogenous or exogenous threat. In COVID-19, the corporal propagation of SARS-CoV-2 involves an exacerbated oxidative activity and therefore the overproduction of great amounts of reactive oxygen and nitrogen species (RONS). The endorsement of melatonin as a possible protective agent against the current pandemic is indirectly supported by its widely demonstrated beneficial role in preclinical and clinical studies of other respiratory diseases. In addition, focusing the therapeutic action on strengthening the host protection responses in critical phases of the infective cycle makes it likely that multi-tasking melatonin will provide multi-protection, maintaining its efficacy against the virus variants that are already emerging and will emerge as long as SARS-CoV-2 continues to circulate among us.

Synthesis, antioxidant properties and neuroprotection of α-phenyl-tert-butylnitrone derived HomoBisNitrones in in vitro and in vivo ischemia models.

We herein report the synthesis, antioxidant power and neuroprotective properties of nine homo-bis-nitrones HBNs 1-9 as alpha-phenyl-N-tert-butylnitrone (PBN) analogues for stroke therapy. In vitro neuroprotection studies of HBNs 1-9 against Oligomycin A/Rotenone and in an oxygen-glucose-deprivation model of ischemia in human neuroblastoma cell cultures, indicate that (1Z,1'Z)-1,1'-(1,3-phenylene)bis(N-benzylmethanimine oxide) (HBN6) is a potent neuroprotective agent that prevents the decrease in neuronal metabolic activity (EC50 = 1.24 ± 0.39 µM) as well as necrotic and apoptotic cell death. HBN6 shows strong hydroxyl radical scavenger power (81%), and capacity to decrease superoxide production in human neuroblastoma cell cultures (maximal activity = 95.8 ± 3.6%), values significantly superior to the neuroprotective and antioxidant properties of the parent PBN. The higher neuroprotective ability of HBN6 has been rationalized by means of Density Functional Theory calculations. Calculated physicochemical and ADME properties confirmed HBN6 as a hit-agent showing suitable drug-like properties. Finally, the contribution of HBN6 to brain damage prevention was confirmed in a permanent MCAO setting by assessing infarct volume outcome 48 h after stroke in drug administered experimental animals, which provides evidence of a significant reduction of the brain lesion size and strongly suggests that HBN6 is a potential neuroprotective agent against stroke.

Acetylcholinesterase Inhibition of Diversely Functionalized Quinolinones for Alzheimer's Disease Therapy.

In this communication, we report the synthesis and cholinesterase (ChE)/monoamine oxidase (MAO) inhibition of 19 quinolinones (QN1-19) and 13 dihydroquinolinones (DQN1-13) designed as potential multitarget small molecules (MSM) for Alzheimer's disease therapy. Contrary to our expectations, none of them showed significant human recombinant MAO inhibition, but compounds QN8, QN9, and DQN7 displayed promising human recombinant acetylcholinesterase (hrAChE) and butyrylcholinesterase (hrBuChE) inhibition. In particular, molecule QN8 was found to be a potent and quite selective non-competitive inhibitor of hrAChE (IC50 = 0.29 µM), with Ki value in nanomolar range (79 nM). Pertinent docking analysis confirmed this result, suggesting that this ligand is an interesting hit for further investigation.

Potential of Melatonin as Adjuvant Therapy of Oral Cancer in the Era of Epigenomics.

The wide variety of epigenetic controls available is rapidly expanding the knowledge of molecular biology even overflowing it. At the same time, it can illuminate unsuspected ways of understanding the etiology of cancer. New emerging therapeutic horizons, then, promise to overcome the current antitumor strategies need. The translational utility of this complexity is particularly welcome in oral cancer (OC), in which natural history is alarmingly disappointing due to the invasive and mutilating surgery, the high relapsing rate, the poor quality of life and the reduced survival after diagnosis. Melatonin activates protective receptor-dependent and receptor-independent processes that prevent tissue cancerisation and inhibit progressive tumor malignancy and metastasis. Related evidence has shown that melatonin pleiotropy encompasses gene expression regulation through all the three best-characterized epigenetic mechanisms: DNA methylation, chromatin modification, and non-coding RNA. OC has received less attention than other cancers despite prognosis is usually negative and there are no significant therapy improvements recorded in the past decade. However, a large research effort is being carried out to elucidate how melatonin´s machinery can prevent epigenetic insults that lead to cancer. In the light of recent findings, a comprehensive examination of biochemistry through which melatonin may reverse epigenetic aberrations in OC is an extraordinary opportunity to take a step forward in the clinical management of patients.

A History of the Alexithymia Concept and Its Explanatory Models: An Epistemological Perspective.

Alexithymia, as a theoretical psychotherapeutic construct, finds its origins in psychosomatic medicine, actually being quite old. However, beyond the specific observations and case studies, their characterization and systematization is relatively recent. However, from an epistemological point of view, it remains the subject of debate and therefore remains outside the conventional diagnostic guidelines. Possibly, its history, closely linked to psychoanalysis, as well as the lack of clear empirical references, has turned the alexithymia construct before into a good descriptive and comprehensive framework than in a precise diagnostic model. In this article it is, following the thread conduits of the historical perspective, to deepen these epistemological aspects.

Melatonin: A hypothesis for Kawasaki disease treatment.

Kawasaki disease (KD) is the most common cause of acquired heart disease with unknown etiology among children in developed countries. Acute inflammation of the vasculature, genetic susceptibility and immunopathogenesis based on a transmittable and infectious origin, are the pathologic events involved in the early inflammatory etiology and progression of this disease. However, the exact causes of KD remain unknown. Current proposed recommendations include three therapy lines; firstly, an initial standard therapy with intravenous immunoglobulin (IVIG) followed by aspirin. Secondly, in cases of high risk of coronary lesions, the adjunctive therapy with corticosteroid is commonly considered. Thirdly, in KD patients refractory to the previous therapies, tumor necrosis factor (TNF-α) antagonists are being used to modulate pro-inflammatory cytokines. In view of this status quo, our starting hypothesis is that the ubiquitous and non-toxic neurohormone melatonin could be of critical importance in developing novel adjuvant therapies against KD, as it occurs with a plethora of other diseases. Considering its pleiotropic properties, particularly its antiinflammatory and immunoregulatory capacities, melatonin should be of great therapeutic interest for helping to control the main pathologic features of KD patients. In addition, this multifunctional indole has a safe pharmacological profile, enhancing the therapeutic activity of several drugs and reducing their possible side effects. Consequently, melatonins actions to manage KD need to be tested in further clinical studies.

A History of the Pharmacological Treatment of Bipolar Disorder.

In this paper, the authors review the history of the pharmacological treatment of bipolar disorder, from the first nonspecific sedative agents introduced in the 19th and early 20th century, such as solanaceae alkaloids, bromides and barbiturates, to John Cade's experiments with lithium and the beginning of the so-called "Psychopharmacological Revolution" in the 1950s. We also describe the clinical studies and development processes, enabling the therapeutic introduction of pharmacological agents currently available for the treatment of bipolar disorder in its different phases and manifestations. Those drugs include lithium salts, valproic acid, carbamazepine, new antiepileptic drugs, basically lamotrigine and atypical antipsychotic agents (olanzapine, risperidone, quetiapine, ziprasidone, aripiprazole, asenapine, cariprazine and lurasidone). Finally, the socio-sanitary implications derived from the clinical introduction of these drugs are also discussed.

Pócimas de bruja en la literatura del siglo de Oro Español: la otra cara de los agentes terapéuticos y psicotrópicos / Witches' Potions in the Literature of the Spanish Golden Age: The Other Side of the Therapeutic and Psychotropic Agents

Los textos literarios del Siglo de Oro constituyen una interesante fuente para el estudio de la sociedad española tardorrenacentista y novobarroca, incluyendo sus figuras más marginales. En el presente trabajo, hemos analizado el mundo mágico de brujas y hechiceras desde la perspectiva del uso extraterapéutico de agentes farmacológicos y psicotrópicos, a través de los principales autores áureos, centrándonos, básicamente, en Miguel de Cervantes y Lope de Vega. Se han estudiado los principales agentes empleados en la elaboración de las pócimas venenosas de bruja, destacando las plantas alucinógenas de la familia de las Solanaceae (beleño, mandrágora, belladona, estramonio, solano, eléboro), además de otras, como el acónito, la cicuta, la adelfa, la verbena o la adormidera. Otras sustancias de procedencia animal o mineral también se emplearon en la confección de estos preparados (sapos, arsénico). Finalmente, se han analizado las posibles fuentes documentales en materia científica que pudieron utilizar estos dos destacados literatos, como el Dioscórides comentado por Andrés Laguna en ambos casos, y la Historia Natural de Plinio, comentada por Francisco Hernández y Gerónimo de Huerta, y el opúsculo Il Sapere Util'e Delettevole de Constantino Castriota, en el caso particular de Lope de Vega.

The literary texts of the Golden Age are an interesting source for the study of Spanish late Renaissance and early Baroque society, including their most marginal figures. In the present work, we have analyzed the magical world of witches and sorceresses from the perspective of extra-therapeutic use of pharmacological and psychotropic substances, through the main golden authors, focusing basically on Miguel de Cervantes and Lope de Vega. The main agents used in the production of witches poisonous potions have been studied, highlighting the hallucinogenic plants of the Solanaceae family (henbane, mandrake, belladonna, jumsonweed, nightshade, hellebore), in addition to others, such as aconite, hemlock, oleander, vervain or poppy. Other substances of animal or mineral origin were also used in the preparation of these compounds (toads, arsenic). Finally, we have analyzed the possible documentary sources in scientific matter that could be used by these two prominent writers, such as the Dioscorides commented by Andrés Laguna in both cases, and Pliny's Natural History, commented on by Francisco Hernández and Gerónimo de Huerta, and the booklet Il Sapere Util'e Delettevole by Constantino Castriota, in the particular case of Lope de Vega.

Synergistic antinociceptive interaction of Syzygium aromaticum or Rosmarinus officinalis coadministered with ketorolac in rats.

Syzygium aromaticum (L.) Merr. & L.M. Perry (Mirtaceae) and Rosmarinus officinalis L. (Lamiaceae) are both medicinal plants used for centuries to alleviate pain. The aim of the study was to demonstrate the therapeutic potential utility of herb-drug association of S. aromaticum essential oil or R. officinalis ethanolic extract coadministered with ketorolac. Antinociceptive pharmacological interaction was investigated by an isbolographic study using the formalin test in rats. Both alone and in combination with ketorolac; S. aromaticum and R. officinalis produced a dose-dependent antinociceptive response. To plot the isobologram, we used the effective dose 50 of each one component in a fixed 1:1 ratio. The isobolographic analysis showed that, in both combinations, ketorolac plus essential oil S. aromaticum and ketorolac plus ethanolic extract R. officinalis, the experimental value (Zexp) was lower than the theoretical value (Zadd). In addition, this study shows that eugenol, a metabolite present in S. aromaticum, and ursolic acid, a metabolite present in R. officinalis, also synergized the antinociceptive effect of ketorolac. While, the oleanolic acid present in both medicinal species did not show a synergistic antinociceptive effect in combination with ketorolac. No adverse effects were observed with these herb-drug interactions. These findings suggest that essential oil S. aromaticum and ethanolic extract R. officinalis could be useful in combination with ketorolac for the treatment of inflammatory pain.

La materia terapéutica en La Arcadia, de Lope de Vega / The therapeutic subject in La Arcadia by Lope de Vega

En la actualidad, aún se desconoce el verdadero alcance de la vasta cultura de Lope de Vega, pues, aunque se sabe que fue un gran lector, que legó más de 1500 libros, sus títulos se han perdido a lo largo de la historia. No obstante, en sus obras trasciende una serie de textos que contribuyeron a su formación. En el presente trabajo se analiza La Arcadia (1598), considerada la novela pastoril más erudita del Siglo de Oro, desde la perspectiva de los agentes terapéuticos. En esta obra se mencionan remedios de procedencia herbal (romero, helenium, verbena, lupino, narciso, lirio, jacinto, lechuga o lino), de procedencia mineral (rubí, diamante, esmeralda, pórfido y oro) y también de procedencia animal (sustancias obtenidas del asno, caballo, conejo, zorro, víboras o arañas, entre otros animales). Los resultados confirman que Lope de Vega pudo utilizar una serie de textos científicos en sus citas sobre la materia terapéutica. Entre ellos cabe destacar a Andrés Laguna y su Dioscórides y Plinio el Viejo, cuya Historia Natural pudo haber consultado como fuente primaria, a través de alguna traducción comentada, como la de Gerónimo de Huerta o a través de alguna otra obra basada en ella, como el opúsculo de Constantino Castriota, pues, en este último caso, se encuentran párrafos muy similares y, en algunos casos, casi literales.

Nowadays, the true extent of the vast culture of Lope de Vega is still largely unknown. Although it is known that he was a great reader, who bequeathed more than 1500 books, his titles have been lost throughout history. However, a series of texts that contributed to his education become known in his works. In the present paper, La Arcadia (1598), considered the most erudite pastoral romance of Spanish Golden Age, is analyzed from the therapeutic perspective. Remedies of herbal origin (rosemary, helenium, verbena, lupine, narcissus, lily, hyacinth, lettuce or flax, among others), of mineral origin (ruby, diamond, emerald, porphyry and gold) and also of animal origin (substances obtained from donkeys, horses, rabbits, foxes, vipers or spiders, among other animals) are mentioned in this novel. The results achieved confirm that Lope de Vega was able to use a series of scientific texts in his quotations on the therapeutic subject. Among them, it is worth mentioning Andres Laguna (and his Dioscorides), and Pliny the Elder, whose Natural History could have been consulted as a primary source, through some commented translation, such as that of Geronimo de Huerta, or through some other work based on it, like Constantino Castriota's opuscule. In the latter case, there are very similar and, in some cases, almost literal paragraphs.

The effectiveness of lurasidone as an adjunct to lithium or divalproex in the treatment of bipolar disorder.

The majority of patients with bipolar disorder spend a lot of time in depressive episodes that impose a great burden on patients, caregivers, and society and accounts for the largest part of the morbidity-mortality of the illness. Lurasidone is an atypical antipsychotic with a potent binding affinity as antagonist for D2, 5-HT2A, 5-HT7, and partial agonist at 5-HT1A receptors. Affinity for other receptors as H1 and muscarinic were negligible. Lurasidone was approved in 2010 for the treatment of schizophrenia and recently, 2013, for bipolar depression in monotherapy and an adjunct to lithium or valproate. Clinical trials have established that lurasidone adjuvant to lithium or valproate has more efficacy than the placebo and is associated with minimal weight gain and no clinically meaningful alterations in glucose, lipids, or the QT interval. Additional studies are desirable to know the clinical profile of lurasidone in long-term treatment, in patients with bipolar II disorders, and versus other antipsychotic agents.

Endogenous opioids participation in the effect of Rosmarinus officinalis L. in the visceral, inflammatory and gout arthritis nociception in rodents / Participación de los opioides endógenos en el efecto de Rosmarinus officinalis L. en la nocicepción visceral, inflamatoria y artritis gotosa en roedores

The aim of this study was to investigate the endogenous opioid participation in the antinociceptive effect of R. officinalis aerial parts in experimental models of visceral, inflammatory and gout arthritis nociception. Acid-acetic induced writhing and formalin tests as well as the pain-induced functional impairment model in the rat (PIFIR) assay were studied. Antinociceptive doses of R. officinalis via oral, alone and in presence of an opioid antagonist were evaluated in comparison to the reference analgesic drug tramadol (31.6 and 50mg/kg i.p., in mice and rats, respectively). The antinociceptive effect of R. officinalis at a 300mg/kg dosage was significantly reverted in presence of 1.0mg/ kg s.c. of naloxone in writhing and formalin tests. Concerning PIFIR model, significant antinociceptive response produced for 1000 and 3000mg/kg was not inhibited in presence of 1.0 or 3.16mg/kg, s.c. of naloxone. In the antinociceptive effect of tramadol, naloxone produced partial inhibition in all models tested. These results suggest that antinociceptive and anti-inflammatory activities of R. officinalis aerial parts involve endogenous opioids, but activation of these mediators depends on the experimental model and the physiological process of the induced nociception.

El objetivo de este estudio fue investigar la participación de los opioides endógenos en el efecto antinociceptivo producido por un extracto preparado con las partes aéreas de Rosmarinus officinalis en modelos experimentales de nocicepción visceral, inflamatoria y tipo artritis gotosa. Para la inducción de nocicepción visceral e inflamatoria se utilizaron los modelos de estiramiento abdominal "writhing" y de formalina intraplantar al 1 %, respectivamente, en ratones. A su vez, para la nocicepción de tipo artritis gotosa se utilizó el modelo de disfunción inducida por ácido úrico al 20% intraarticular en ratas conocido como PIFIR (por sus siglas en inglés). Dosis antinociceptivas de R. officinalis vía oral se evaluaron solas y en presencia del antagonista de opioides endógenos naloxona. Adicionalmente, dicho efecto se comparó con el fármaco analgésico de referencia tramadol (31.6 y 50mg/kg i.p., en ratones y ratas, respectivamente). El efecto antinociceptivo de R. officinalis significativo en la dosis de 300mg/kg se revirtió en presencia de 1mg/kg s.c. de naloxona en las pruebas de estiramiento abdominal y formalina. En cuanto al modelo PIFIR, la respuesta antinociceptiva producida por 1000 y 3000mg/kg no se inhibió en presencia de 1 o 3.16mg/kg, s.c. de naloxona. En el efecto de tramadol, opioide atípico, la naloxona produjo inhibición parcial de la respuesta antinociceptiva en todos los modelos probados. Los resultados sugieren que la actividad antinociceptiva producida por el extracto de las partes aéreas de R. officinalis involucra al sistema de opioides endógenos, pero la presencia de estos mediadores depende del tipo de estímulo y del proceso fisiológico involucrado en la nocicepción inducida.

Anti-nociceptive and anti-inflammatory activities of the Agastache mexicana extracts by using several experimental models in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Agastache mexicana is a plant that has long been used in large demand in Mexican folk medicine to treat pain, among others affections. Nevertheless, no scientific data confirming its use have been reported. The aim of this investigation was to examine the spectrum of antinociceptive activity of A. mexicana by using different experimental models of nociception in rodents. MATERIAL AND METHODS: Nociceptive activity was induced 30 min post treatment of different doses of hexane, ethyl acetate and methanol extracts from A. mexicana aerial parts. The writhing test in mice, and the formalin and plantar tests as well as the pain-induced functional impairment assay in rats (PIFIR model) were the experimental nociceptive models used. Antinociceptive response of the organic extracts was compared to that observed with the analgesic drug tramadol. RESULTS: A. mexicana organic extracts produced a dose-dependent and significant inhibition of the abdominal constrictions caused by 1% acetic acid injection (i.p.) in mice. A maximal antinociceptive effectiveness obtained with tramadol was also observed with the administration of hexane and ethyl acetate extracts in comparison to less effectiveness obtained with the methanol extract. At the same range of doses, A. mexicana organic extracts inhibited the behavioral responses in both phases of the formalin pain test, in which a more intense effect was observed in the inflammatory phase than in the neurogenic stage. With regard to the plantar test and PIFIR model, a significant but not dose-dependent antinociceptive response was observed at specific doses that depended on the organic extract evaluated. CONCLUSION: The antinociceptive activity of A. mexicana aerial parts depends on the intensity of the painful stimulus induced and involves different kinds of constituents. Our present results reinforce the use of this species in traditional medicine and its utility for pain treatment mainly associated with inflammation.

Hesperidin produces antinociceptive response and synergistic interaction with ketorolac in an arthritic gout-type pain in rats.

Hesperidin occurs in greatest concentration in plants from the Rutaceae and Lamiaceae families. In human nutrition it contributes to the integrity of blood vessels and its deficiency in the diet has been linked to abnormal capillary leakiness as well as pain. In this study, the bioflavonoid hesperidin was identified as an active compound in an ethanol extract of the Rosmarinus officinalis aerial parts tested in the pain-induced functional impairment model in the rat (PIFIR) as an assay of inflammatory and chronic nociception similar to that observed in clinical gout. Hesperidin produced a dose-dependent and significant response with an ED25=1666.72 mg/kg in comparison to an ED25=302.90 mg/kg for the extract or an ED25=0.47 mg/kg for the reference drug ketorolac in the PIFIR model. Although the antinociceptive response of R. officinalis was reverted in presence of the opioid antagonist naloxone (10 mg/kg, s.c.) and the 5HT(1A) antagonist WAY100635 (0.12 mg/kg, s.c.), the hesperidin response was not modified by naloxone (10 mg/kg), WAY100635 (0.12 mg/kg), bicuculline (1 mg/kg, s.c.), flumazenil (10 mg/kg, i.p.) or caffeine (1 mg/kg, s.c.). Nevertheless, it was reduced in presence of capsazepine (10 or 20 mg/kg, s.c.) suggesting the participation of the TRPV1 receptor, which was reinforced when hesperidin significantly reduced the capsaicin-induced nociceptive response. A synergistic interaction was also observed when antinociceptive doses of hesperidin were combined with those of ketorolac producing 15 combinations mainly in additive and supra-additive responses. These results provide evidence for the antinociceptive activity of hesperidin and demonstrate synergistic response when combined with ketorolac, possibly by involvement of the TRPV1 receptor, suggesting their clinical potential in pain therapy.

[The historical background of the pineal gland: I. From a spiritual valve to the seat of the soul]. / El devenir histórico de la glándula pineal: I. De válvula espiritual a sede del alma.

INTRODUCTION: Throughout history, the special anatomical location of the pineal gland in the central nervous system has given rise to a number of physiological hypotheses regarding the functional role of this organ. DEVELOPMENT: In classical ancient times, the pineal body (conarium) was considered to be a sort of valve-like sphincter that regulated the flow of the spiritus animalis at the ventricular level. But it was not until the 17th century that the pineal gland finally reached its highest levels of physiological significance, when Rene Descartes considered it to be the anatomical structure that housed the seat of the soul. CONCLUSIONS: The Cartesian hypotheses regarding the pineal gland did not arouse much interest in the scientific community of the time, and attention to this organ dwindled from then until the 20th century, when its neuroendocrinological nature was finally confirmed.

Antinociceptive activity of Annona diversifolia Saff. leaf extracts and palmitone as a bioactive compound.

Annonas are consumed as fresh fruits, but are also widely used in folk medicine for treating pain and other ailments. Antinociceptive properties of the Annona diversifolia ethanol crude extract were tested using the pain-induced functional impairment model in rat (PIFIR) and the writhing test in mice. The ethanol extract caused a 25% recovery of limb function in rats; this response was significant and dose-dependent. Furthermore, this extract produced a similar antinociceptive response (ED(50)=15.35 mg/kg) to that of the reference drug tramadol (ED(50)=12.42 mg/kg) when evaluated in the writhing test in mice. Bio-guided fractionation yielded hexane and acetone active fractions from which the presence of palmitone and flavonoids was respectively detected. Palmitone produced an antinociceptive response with an ED(50)=19.57 mg/kg in the writhing test. Antinociceptive responses from ethanol extract and tramadol were inhibited in the presence of either naloxone (1mg/kg, s.c.)--an antagonist of endogenous opioids--or WAY100635 (0.8 mg/kg, s.c.)--a 5-HT(1A) serotonin receptor antagonist. These results provide evidence that A. diversifolia possesses antinociceptive activity, giving support to their traditional use for treatment of spasmodic and arthritic pain. In addition, our results suggest the participation of endogenous opioids and 5-HT(1A) receptors in this antinociceptive response.

Antinociceptive effect and GC/MS analysis of Rosmarinus officinalis L. essential oil from its aerial parts.

The rationale of this investigation was to examine the antinociceptive properties of the essential oil obtained from Rosmarinus officinalis aerial parts, using a rat model of arthritic pain. The essential oil (100, 300 and 600 mg/kg, I. P.) produced a dose-dependent antinociceptive effect, manifested as a significant reduction in the dysfunction in the pain-induced functional impairment model in the rat (PIFIR model), mainly at high doses. Chemical constituents of the essential oil were further analyzed by gas chromatography-mass spectrometry (GC/MS). The major compounds in the essential oil were alpha-pinene (14.10 %), camphene (11.47 %), beta-pinene (12.02 %), myrcene (3.31 %), alpha-phellandrene (7.87 %), eucalyptol (8.58 %), 2-bornanone (3.42 %), camphor (8.75 %), isoborneol (3.48 %), borneol (4.85 %) and borneol acetate (6.49 %). The antinociceptive effects of R. officinalis essential oil were tested in combination with 0.12 mg/kg WAY100635, s. c. (an antagonist of 5-HT(1A) receptors) or 1 mg/kg naloxone, i. p. (an antagonist of endogenous opioids receptors), demonstrating in both cases an inhibition of the antinociceptive response. This study suggests an involvement, at least in part, of the serotonergic system via 5-HT(1A) receptors and endogenous opioids in the antinociceptive effect of R. officinalis essential oil in the PIFIR model.

Antinociceptive activity of Tilia americana var. mexicana inflorescences and quercetin in the formalin test and in an arthritic pain model in rats.

Tilia species are well known around the world for their properties in traditional medicine. Antinociceptive activity of hexane, methanol and aqueous extracts from Tilia americana var. mexicana inflorescences was evaluated in the pain-induced functional impairment model in rats (PIFIR). A preliminar 300 mg/kg dosage of aqueous extracts i.p., but not the same dose of methanol or hexane extract, produced an antinociceptive response in rats similar to that of tramadol (17.8 mg/kg i.p.). A dose-response curve from aqueous extract allowed the determination of ED(50) = 364.97 mg/kg in comparison to ED(50) = 10.35 mg/kg for tramadol in this model. A previous HPLC-DAD analysis corroborated by an HPLC-MS technique in this study demonstrated the flavonoid composition in this Tilia aqueous extract revealing the presence of glycosides mainly derived from quercetin. Thus, Tilia aqueous extract and quercetin were tested at 30 and/or 100 mg/kg dosages i.p. in the PIFIR and formalin models producing a significant and dose-dependent antinociceptive response resembling that produced by a total and a partial agonist of 5-HT(1A) receptors like 8-OH-DPAT (0.1 mg/kg, s.c.) and buspirone (5 mg/kg, i.p.), respectively. In all the treatments, antinociceptive response was inhibited in the presence of WAY 100635 (0.12 mg/kg, i.p.). Our results support the analgesic activity of T. americana var. mexicana inflorescences attributed by folk medicine; they also indicate that quercetin is partly responsible for this pharmacological activity that is likely mediated by serotonin 5-HT(1A) receptors.