Myocardial repair with long-term and low-dose administration of a nitric oxide synthesis inhibitor. Myofibroblasts, type III collagen and fibronectin

OBJECTIVE: To study the healing process of the myocardium in hypertensive rats undergoing inhibition of nitric oxide synthesis. METHODS: Two groups of animals were studied: one received L-NAME, 12mg/kg/day, and the other was a control group. The presence of type III collagen, fibronectin, and alpha-smooth muscle actin-positive cells was assessed by immunohistochemistry. RESULTS: Fibronectin was seen in both early and late lesions, while type III collagen was seen mainly in areas of incomplete healing, situated among myocytes and around the intramyocardial branches of the coronary arteries. Areas representing early and late lesions showed a population of spindle-shaped cells. Immunohistochemistry showed that these cells were positive for alpha-smooth muscle actin. CONCLUSION: In the myocardium of hypertensive rats, the alpha-smooth muscle actin-positive cells are related to the accumulation of type III collagen and fibronectin in the areas of myocardial damage.

Designation of natural monuments by the local administration: the example of Viana do Castelo municipality and its engagement with geoconservation (NW Portugal)

"First online: 11 April 2016"

Procesos de plasticidad sin��ptica en gyrus dentado hipocampal durante la administraci��n cr��nica y el s��ndrome de abstinencia a coca��na. Synaptic plasticity in hippocampal dentate gyrus during chronic administration and withdrawal from cocaine.

Los procesos neuronales adaptativos que se observan como consecuencia de la administraci��n cr��nica de drogas de abuso, son similares a los procesos pl��sticos que subyacen al aprendizaje y la memoria. Por otra parte, el hipocampo forma parte del circuito neuronal responsable de los cambios conductuales observados como consecuencia de la administraci��n cr��nica de diferentes drogas de abuso. De acuerdo con esto, resultados previos de nuestro laboratorio demostraron que la plasticidad sin��ptica en el hipocampo y las claves contextuales relacionadas con la administraci��n de la droga, son relevantes para el incremento de la plasticidad hipocampal por la administraci��n cr��nica de diazepam. Espec��ficamente en el gyrus dentado hipocampal se han descripto fen��menos pl��sticos relacionados con la exposici��n cr��nica a psicof��rmacos, tales como facilitaci��n en la transmisi��n sin��ptica, disminuci��n de la proliferaci��n celular y el aumento del factor de transcripci��n ?Fos B. Debido a la correlaci��n existente entre los mecanismos de plasticidad neuronal, los aprendizaje asociativos y formaci��n de memorias y aquellos responsables de la adicci��n, el objetivo general de este trabajo es caracterizar los cambios inducidos por la exposici��n repetida de coca��na y durante el periodo de abstinencia, en la excitabilidad neuronal de las c��lulas del gyrus dentado hipocampal, los canales i��nicos afectados y los posibles mecanismos bioqu��micos involucrados en dichos cambios, que podr��an explicar las alteraciones conductuales observadas despu��s de dicho tratamiento. Con este prop��sito, se estudiar��: 1) la plasticidad sin��ptica (potenciaci��n a largo plazo, LTP y depotenciaci��n a largo plazo, LTD) en el gyrus dentado, mediante registros electrofisiol��gios multiunitarios; 2)la excitabilidad de las c��lulas granulares del gyrus dentado y la actividad de los canales i��nicos, utilizando la t��cnica de patch clamp; 3) las alteraciones en la neurotransmisi��n glutamatergica, midiendo los niveles del neurotransmisor <i>in vivo</i>, utilizando la t��cnica de microdi��lisis; el tr��fico de receptores glutamat��rgicos, utilizando la t��cnica de western-blott, 4) la participaci��n del ��xido n��trico en los cambios adaptativos observados como consecuencia de la sensibilizaci��n a coca��na. Adem��s, mediante la utilizaci��n de t��cnicas comportamentales (avoidance inhibitorio), se estudiar��n las posibles alteraciones de conductas que se sabe dependen de la integridad funcional del hipocampo.En relaci��n a los resultados del presente proyecto se espera obtener un incremento en la plasticidad sin��ptica, en la excitabilidad neuronal de las c��lulas granulares del gyrus dentado de la formaci��n hipoc��mpica, en la liberaci��n extracelular de glutamato <i>in vivo</i>, como as�� tambi��n en el tr��fico de receptores glutamat��rgicos. Adem��s se espera obtener un aumento de las v��as de se��alizaci��n activadas por la acci��n de glutamato, como la de ��xido n��trico/GMPc, como consecuencia de la administraci��n cr��nica de coca��na. Con este aumento global de la plasticidad sin��ptica hipocampal, las conductas dependientes de esta estructura debieran estar facilitadas, demostrando as�� una participaci��n activa del hipocampo en los procesos de sensibilizaci��n y posiblemente en la adicci��n a psicoestimulantes. La caracterizaci��n del impacto del desarrollo de sensibilizaci��n a coca��na en la excitabilidad neuronal en el hipocampo, sobre los sistemas de neurotransmisi��n y las v��as de se��alizaci��n involucradas contribuir��an a dilucidar los mecanismos que contribuyen al desarrollo de sensibilizaci��n a coca��na, los cuales podr��an representar potenciales blancos terap��uticos para el tratamiento de la adicci��n, considerando principalmente aspectos espec��ficos de la actividad el��ctrica neuronal y la plasticidad sin��ptica asociada con las diferentes fases del ciclo de la adicci��n.

Co-administration of Apelin and T4 Protects Inotropic and Chronotropic Changes Occurring in Hypothyroid Rats

AbstractBackground:One of the most important thyroid hormone targets is the cardiovascular system. Hemodynamic changes, such as decreased resting heart rate (HR), myocardial contractility, and cardiac output, and increased diastolic pressure and systemic vascular resistance, have been observed in hypothyroid patients. Moreover, in these patients, ECG changes include sinus bradycardia and low voltage complexes (P waves or QRS complexes).Objective:This study aimed at evaluating the prophylactic effect of apelin on HR changes and QRS voltage that occur in propylthiouracil (PTU)-induced hypothyroid rats.Method:In this study, 48 adult male Wistar rats weighing 170-235g were randomly divided into 6 groups: Control group (normal saline ip injection + tap water gavage); P group (PTU 0.05%, in drinking water); A group (apelin 200 ��g.kg-1.day-1, ip); PA group [co-administration of PTU and apelin]; PT group [co-administration of PTU + T4 (0.2 mg/g per day, gavage)]; and PAT group (co-administration of PTU, apelin and T4). All experiments were performed for 28 consecutive days, and then the animals were anesthetized with an ip injection of ketamine (80 mg/kg) and xylazine (12 mg/kg). Lead II electrocardiogram was recorded to calculate HR and QRS voltage.Results:Heart rate and QRS voltage increased more significantly in the hypothyroid group that consumed both apelin and T4 (201 �� 4 beat/min, 0.71 �� 0.02 mv vs. hypothyroid 145 �� 9 beat/min, 0.563 �� 0.015 mv; respectively).Conclusion:The co-administration of apelin and T4 showed a protective effect on QRS voltage and HR in PTU&#8209;induced hypothyroid rats.

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.81 (1983)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.91 (1993)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.74 (1976)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.71 (1973)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.69 (1971)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.73 (1975)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.72 (1974)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.70 (1972)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.101 (2003)

Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service.

v.93 (1995)