Emilia Díaz

• Doctora en Ciencias. Mención Farmacología.
• Professor at Central University of Venezuela

Detection and transduction of environmental signals, constitute a prerequisite for successful parasite invasion; i.e., Leishmania transmission, survival, pathogenesis and disease manifestation and dissemination, with diverse molecules functioning as inter-cellular signaling ligands. Receptors [i.e., G protein-coupled receptors (GPCRs)] and their as...

Chemotactic responses play a significant role during Leishmania (V.) braziliensis differentiation through its life cycle and during infection. The aim of this description has been to portray the modified “two-chamber capillary chemotaxis assay” as a technique useful for quantitative in vitro evaluation of Leishmania chemotaxis after reviewing the m...

Cell-cell interaction and active migration (and invasion) of parasites into skin host-cell(s) are key steps for successful infection by Leishmania. Chemotaxis constitutes a primordial chapter of Leishmania-host cell interaction, potentially modulated by neuropeptides released into the skin due, for example, to the noxious stimuli represented by the...

One of the main challenges of therapeutic tools for the treatment of parasitic diseases, including leishmaniasis, is the interwinned relationship between therapeutic failure and drug resistance. In fact, some field parasites might be naturally resistant to classical drugs and additionally, current therapies may induce drug resistance. In fact, trea...

The Calcitonin-Like Receptor (CLR) belongs to the classical seven-transmembrane segment molecules coupled to heterotrimeric G proteins. Its pharmacology depends on the simultaneous expression of the so-called Receptor Activity Modifier Proteins (RAMP-) -1, -2 and -3. RAMP-associated proteins modulate glycosylation and cellular traffic of CLR, there...

El sistema adrenomedulinérgico cerebral es uno de los sistemas que participan en la regulación del balance hidromineral. La administración central de adrenomedulina (AM) aumenta la presión arterial, produce natriuresis, liberación de oxitocina y vasopresina desde el núcleo paraventricular hipotalámico. La evidencia indica que la oxitocina es una ho...

La cirugía bariátrica (CB) consiste en una serie de procedimientos quirúrgicos que actúan restringiendo la capacidad gástrica y/o produciendo malabsorción parcial de los alimentos debido a diversas alteraciones fisiológicas de los péptidos incretinas, los ácidos biliares y del sistema autónomo; cuyo objetivo principal es generar pérdidas significat...

Palabras clave: adrenomedulina; riñón; insuficiencia renal crónica. Resumen. La adrenomedulina (ADM), péptido vasodilatador de 52 aminoácidos, ubícuo, posee múltiples efectos fisiológicos que contribuyen a respuestas homeostáticas. Se encuentra en concentraciones importantes en la glándula suprarrenal, el pulmón, el sistema cardiovascular y el rena...

In the sand-fly mid gut, Leishmania promastigotes are exposed to acute changes in nutrients, e.g. amino acids (AAs). These metabolites are the main energy sources for the parasite, crucial for its differentiation and motility. We analysed the migratory behaviour and morphological changes produced by aliphatic, monocarboxylic, dicarboxylic, heterocy...

Besides infection with drug-resistant parasites, therapeutic failure in leishmaniasis may be caused by altered drug pharmacokinetics, re-infection, and host immunologic compromise. Our aim has been to evaluate if relapses that occur in patients suffering from diffuse cutaneous leishmaniasis (DCL) associate with changes in the fitness of infecting o...

Chemotactic responses play a significant role during Leishmania differentiation, as well as in the course of parasite-host-cell interaction, a process that precedes a successful infection. The present study uses the modified "two-chamber capillary assay" to quantitatively evaluate the chemotactic properties and the toxic activities of methotrexate...

Central to the concept of host-parasite interaction is the idea that adaptation to the stress living conditions imposed by the pressure of a drug is not cost-free. Costs arise if adaptation represents a conflict with traits that may compromise intrinsically parasite properties essential for its survival like, for example, parasite virulence. Such t...

Several techniques have been used to study the mechanisms by which receptors recognize ligands, one of them being quantitative structure activity relationship analysis of compounds. This method facilitates the description of molecular details involved in drug recognition by molecular receptors, as well as the molecular mechanism involved. This tech...

Chemotactic responses play a significant role, both during Leishmania braziliensis differentiation through its life cycle and during infection, a process that inoculates parasites into a mammalian host and results in the acquisition of the disease leishmaniasis. This paper reviews the methods described until now to assess chemotaxis in vitro in Lei...

A source of chemotherapeutic failure in anti-infective therapies is the active movement of drugs across membranes, through ATP-binding cassette (ABC) transporters. In fact, simultaneous administration of therapeutic drugs with ABC transporter blockers has been invoked to be the way to actively prevent the emergence of drug resistance. Herein, we de...

Leishmaniasis is a disease caused by at least 17 different species of protozoan Leishmania parasites and currently affects around 12 million people living mostly in tropical and subtropical areas. Failure to treat leishmaniasis successfully is often due to drug resistance. However, there are no cellular and molecular markers of chemoresistance agai...

Therapeutic failure in leishmaniasis is a common problem in endemic areas. This could be attributed to altered drug pharmacokinetics, re-infection, or immunologic compro mise of the host. However, strong indicators suggest that it may be partly due to drug resistance. Until now, there are no markers of chemo-resistance against leishmanicidal drugs,...

Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) belong to CGRP superfamily. Both peptides have overlapping biological actions particularly in regard to their very potent vasodilator properties. AM and CGRP binding sites are widely expressed in the central nervous system, in areas such as the hypothalamus and the rat cerebelar cor-tex...

Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) belong to CGRP superfamily. Both peptides have overlapping biological actions particularly in regard to their very potent vasodilator properties. AM and CGRP binding sites are widely expressed in the central nervous system, in areas such as the hypothalamus and the rat cerebelar cortex....

The renin angiotensin system (RAS) is considered to play an important physiological role in the regulation of body fluid. Intracerebroventricular administration of renin or angiotensin II (Ang II) increases blood pressure, sympathetic outflow, water intake, sodium excretion and oxytocin and vasopressin release and decreases urine volume. Evidence i...

Adrenomedullin (AM) is a hypotensive peptide that is highly expressed in the central nervous system. Central AM increases water and salt intake, arginine-vasopressin secretion and produces diuresis and natriuresis. In adrenal glands AM inhibits aldosterone (ALD) secretion induced by angiotensin II, KCL or ACTH. We assessed the hypothesis that a dim...

Seeking for new medicinal compounds in plants used in traditional medicine, which grow in Venezuela, we investigated the anti-inflammatory activity of the leaf hexane extract (HE) and several fractions obtained from sp. Bursera simaruba (L.) Sarg. (Indio desnudo) using carrageenan-induced paw edema inflammation. Oral administration of leaf HE as we...

Intracerebroventricular (IVT) administration of adrenomedullin (AM) to conscious male hydrated rats increases urinary volume and sodium excretion. The possible involvement of brain dopamine (DA) system on the renal action of IVT-AM was investigated. AM-induced diuretic and natriuretic action was prevented following selective central dopaminergic de...

Experiments were conducted to investigate the role of brain the α1- α2 and β-adrenergic receptors on the renal effects elicited by central injection of ETs. Cerebroventricular administration of endothelins (ETs) to conscious male hydrated rats resulted in an increase in urinary sodium excretion at 1, 3 and 6 hr period of urine collection. Central a...

Con el fin de establecer el subtipo de receptor que media la acción diurética y natriurética inducida por la adrenomedulina (AM) intracerebroventricular (IVT), se evaluó esta respuesta en ratas pretratadas con AM(22-52), un antagonista específico del receptor de la AM (AM-R), o con CGRP(8-37), un antagonista de los receptores tipo 1 del péptido rel...

To determine pharmacological specificity of intracerebroventricular (IVT) administration of adrenomedullin (AM) on water and sodium excretion, studies were performed in rats pretreated with AM (22-52), a putative AM-receptor antagonist or CGRP(8-37), a ligand that preferentially antagonizes the CGRP(1)-receptor subtype. In addition, the effects of...

Intracerebroventricular administration of rat adrenomedullin (AM) to conscious hydrated or salt-loaded rats, resulted in a significant increase in urinary volume. The diuretic effect of adrenomedullin occurred during the 6-h period of urine collection and was most effective during the 3 and 6 h. Most remarkably, AM given IVT induced a dose-related...

Therapeutic failure in leishmaniasis is a common problem in endemic areas. This could be attributed to altered drug pharmacokinetics, re-infection, or immunologic compromise of the host. However, strong indicators suggest that it may be partly due to drug resistance. Until now, there are no markers of chemo-resistance against leishmanicidal drugs,...