Catecholamines reduce transient receptor potential vanilloid type 1 desensitization in cultured dorsal root ganglia neurons.

Sympathetic nervous system and adrenergic receptors are involved in the modulation of dorsal root ganglia neuronal activity, with TRPV1 receptor as an important downstream effector. It is already known that adrenergic sensitization of TRPV1 receptors or catecholamine-induced TRPV1 upregulation are involved in increased excitability and pain via mainly α1 adrenergic receptors, but it is not known if reduced TRPV1 desensitization is involved in this process, as well. Therefore, the aims of this study were to evaluate the effects of epinephrine and norepinephrine on TRPV1 desensitization induced by repeated applications of capsaicin and to assess what would be the involvement of the major α1, α2 and ß adrenergic receptor subtypes. Using calcium microfluorimetry, the effects were evaluated by exposure to 1 µM epinephrine or 10 µM norepinephrine, alone or in the presence of adrenergic receptor inhibitors (phentolamine, prazosin and propranolol) before a 4th capsaicin application in a series of 5 consecutive capsaicin applications. The results showed that both catecholamines produced significant reduction of TRPV1 desensitization, which was mediated by α1, α2 and ß2 receptors. This study completes the general information about TRPV1 sensitization via adrenergic stimulation and may open perspectives for novel pharmacological approaches in skin inflammatory disorders and pain therapy.

A system for applying rapid warming or cooling stimuli to cells during patch clamp recording or ion imaging.

We describe a system for superfusing small groups of cells at a precisely controlled and rapidly adjustable local temperature. Before being applied to the cell or cells under study, solutions are heated or cooled in a chamber of small volume ( approximately 150 microl) and large surface area, sandwiched between four small Peltier elements. The current through the Peltier elements is controlled by a microprocessor using a PID (proportional-integral-derivative) feedback algorithm. The chamber can be heated to at least 60 degrees C and cooled to 0 degrees C, changing its temperature at a maximum rate of about 7 degrees C per second; temperature ramps can be followed under feedback control at up to 4 degrees C per second. Temperature commands can be applied from the digital-to-analogue converter of any laboratory interface or generated digitally by the microprocessor. The peak-to-peak noise contributed by the system does not exceed that contributed by a patch pipette, holder and headstage, making it suitable for single channel as well as whole cell recordings.

Evolution features of hypertensive patients with primary aldosteronism--prospective study.

BACKGROUND: Primary aldosteronism is the leading cause of secondary hypertension, the management of this disease requiring an interdisciplinary approach. OBJECTIVES: Evaluation of evolutionary features of patients with secondary hypertension and primary aldosteronism. METHODOLOGY: We have followed 26 patients diagnosed with secondary hypertension and primary aldosteronism, who were admitted consecutively to "C. I. Parhon" Endocrinology Institute between 2004-2009. Of the 26 patients, 17 had adenoma producer of aldosterone (APA), 8 had bilateral adrenal hyperplasia idiopathic (HIA) and one patient had adrenal carcinoma (with hypersecretion of aldosterone). The mean age of the cohort was of 49.3 years (44.9 years for adenomas and 52.6 years for bilateral hyperplasia). The evaluation of the patients included clinical examination, electrocardiogram, Holter BP, echocardiography and determination of plasma aldosterone and renin. RESULTS: The evolution of the patients with primary aldosteronism was different depending on the anatomoclinic type. In patients with idiopathic bilateral hyperplasia, medical treatment has improved control of hypertension and cardiac and cerebrovascular complications rate was moderate. In patients with unilateral adenoma producing aldosterone, blood pressure had higher values and more frequent complications, but surgical cure of adenomas significantly changed the prognosis of patients. In both cases, the presence of hypokalemia was an additional element of severity. CONCLUSIONS: Regardless of the primary aldosteronism, hypertension was directly involved in cardiac and cerebrovascular complications. Individualization of treatment according to the anatomoclinic type determined a significant improvement of the patients' prognosis.