Navegando por Data de Publicação, começando com "2005-03-21"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 3 de 3

Importância da região AV3V para as respostas pressoras produzidas pela ativação de áreas bulbares
(Universidade Federal de São Carlos, 2005-03-21) Vieira, Alexandre Antonio; Menani, José Vanderlei; https://lattes.cnpq.br/1023597870118105
Cardiovascular responses are integrated at different levels of the central nervous system (CNS). Particularly the hypothalamus and brainstem areas are involved in the control of autonomic responses and among them the cardiovascular responses. Different areas in the brainstem, like the nucleus tract solitarii (NTS), the rostroventrolateral medulla (RVLM), caudoventrolateral medulla (CVLM) and the nucleus ambigus are important to cardiovascular control. These areas of the brainstem that control the cardiovascular system receive information from receptors present in different parts of the body, specially the pressoreceptors and chemoreceptores and control the activity of the autonomic efferents. Injection of the excitatory amino acid glutamate into the NTS in anesthetized rats produces depressor response and bradycardia like barorreflex activation. Differently, in unanesthetized rats, injection of the glutamate into the NTS produces pressor response and bradycardia, similar to chemoreflex activation. The neuropeptide substance P may act as neurotransmitter or neuromodulator of differents cardiovascular reflexes and when injected into the NTS produces pressor response. The RVLM is the main site of sympathetic output to the intermediolateral cell column of the spinal cord. Injection of glutamate into the RVLM increases sympathetic activity and induces pressor response. Hypotalamic areas are also involved in the control of cardiovascular responses. For example, electrolytic lesions in the paraventricular nucleus of the hypothalamus (PVN), reduce the pressor response to chemoreflex activation with potassium cyanide (KCN) iv Another hypothalamic area important for cardiovascular control is the anteroventral third ventricle (AV3V) region. Electrolytic lesion of the AV3V region reduces the cardiovascular responses produced by central colinergic and angiotensinergic activation and abolish many forms of the experimental hypertension in animals. In the present study, in unanesthetized rats, we investigated the effects of acute (1 day) and cronic (15 days) AV3V lesions in the pressor responses produced by NTS activation with injection of the excitatory amino acid glutamate and substance P or injection of glutamate into the RVLM. The responses to activation of the baroreflex and chemoreflex were also tested. Rats with sham or electrolytic lesions of the AV3V region and stainless steel cannulas implanted into the NTS or RVLM were used. Mean arterial pressure (MAP) and heart rate (HR) were recorded in unanesthetized rats. A polyethylene tubing was inserted into the abdominal aorta through the femoral artery on day before the experiments. A second polyethylene tubing was inserted in the femoral vein for the baroreflex and chemoreflex tests. The central injections were made using 5 µl Hamilton syringes. The volume of the central injections into the NTS and RVLM was 100 nl. In sham rats, the injection of glutamate (5 nmol) into the NTS produce pressor response (28 ± 3 mmHg). The same dose of glutamate in acute AV3V-lesioned rats produce hypotension (-26 ± 8 mmHg) in the first day after lesion or did not modify the MAP (2 ± 8 mmHg) fifteen days after AV3V lesion. The bradycardic responses produced by injection of the glutamate into the NTS in acute (-65 ± 23 bpm) or cronic (-90 ± 29 bpm) AV3Vlesioned rats were not different from the bradycardic responses produced by glutamate into the NTS in sham-lesioned rats (-76 ± 13 e -90 ± 15 bpm). Differently, the pressor response produced by injection of substance P (0,5 e 1 nmol) into the NTS in acute (16 ± 2 and 20 ± 2 mmHg, respectively) or chronic AV3V-lesioned rats (18 ± 1 and 20 ± 1 mmHg) were not different from the pressor responses produced by the same doses of substance P into the NTS in acute (20 ± 5 and 22 ± 3 mmHg) or chronic sham rats (19 ± 3 and 25 ± 3 mmHg). The tachycardic responses produced by injection of substance P into the NTS in acute (54 ± 15 and 71 ± 15 bpm) and chronic AV3V-lesioned rats (70 ± 11 and 66 ± 11 bpm) were also not different from the tachycardic responses produced by substance P into the NTS in acute (75 ± 14 and 72 ± 12 bpm) or chronic sham rats (53 ± 16 e 84 ± 7 bpm). The pressor responses produced by injections of glutamate (1, 5 and 10 nmol) into the RVLM in acute (9 ± 4, 39 ± 6 e 37 ± 4 mmHg, respectively) or chronic AV3V-lesioned rats (13 ± 6, 39 ± 4 and 43 ± 4 mmHg, respectively) were significantly reduced compared to the pressor responses of the same doses of glutamate into the RVLM in acute (33 ± 5, 54 ± 3 and 56 ± 8 mmHg, respectively) or chronic sham rats (29 ± 3, 50 ± 2 and 58 ± 3 mmHg, respectively). Glutamate into the RVLM in acute or chronic sham or AV3V lesioned rats produced no significant change in the heart rate. The baroreflex responses produced by iv phenylephrine (5 µg/kg of body weight), sodium nitroprussiade (30 µg/kg of body weight), or the responses produced by chemoreflex activation with iv injection of potassium cyanide (20 and 40 µg/rato) were not modified by acute or chronic AV3V lesion. The results show the importance of the AV3V region for the cardiovascular responses dependent on the activation of the sympathetic nervous system and specially the pressor responses to glutamatergic activation in the NTS and RVLM. The integrity of the AV3V region is important for the pressor responses to injection of glutamate into the NTS and into the RVLM, but not for the pressor response to injection of substance P into the NTS, which suggests that the AV3V lesion does not non specifically affect any pressor mechanism. The AV3V lesions do not modify the baro and chemoreflex responses, suggesting that the sympatoexcitatory responses to chemoreflex activation do not depend unique and exclusively on glutamatergic neurotransmission in the NTS and RVLM.
Mamíferos do cerrado de Mato Grosso, com ênfase no uso do espaço por Cerdocyon thous (Carnivora, Canidae) e Mazama gouazoubira (Artyodctyla, Cervidae)
(Universidade Federal de São Carlos, 2005-03-21) Santos Júnior, Tarcísio da Silva; Alho, Cléber José Rodrigues; https://lattes.cnpq.br/3871915319484773; https://lattes.cnpq.br/5540188077381302
This research was developed in the Cerrado environments located in the municipalities of Chapada dos Guimarães (MT) and Rosario Oeste (MT), to study the abundance of Terrestrial Mammals of Medium and Large Size as well as the use of space by crab-eating fox, Cerdocyon thous, and the gray brocket deer, Mazama gouazoubira. It was conducted between 2000 and 2004 in four areas: reservoir of Manso hydroelectric powerplant (APM-Manso: 14°52'15" S, 55°47'5"W), Chapada dos Guimarães National Park (PARNA-CG: 15°24'13"S, 55°49'50"W), Comunidade São Jerônimo (CSJ: 15°25'40"S, 55°53'54"W) and Panflora farm (Panflora: 15°4'43"S, 56°33'15"W). Line transects were sampled by car in order to study abundance of mammals. The effort of covering 1560 km allowed registering 14 out of the 21 species expected to occur in the region. The C. thous was the most abundant in all areas, followed by M. gouazoubira, which in turn was less abundant than the pampas deer, Ozotoceros bezoarticus in PARNACG. The results showed differential density of species between the sites surveyed. The study of the use of space by C. thous and M. gouzoubira was performed by equipping adults with conventional biotelemetry radiotransmiters. Research on C. thous was developed in the APM-Manso and Panflora to study the size and overlap of its home range and survival. The species M. gouazoubira was monitored only in the APM Manso with the aim of studying relocated individuals concerning their survival, the displacement pattern in post- releasing, along with the size and overlap of home range. The size of the home range of C. thous of APM Manso ranged from 128 to 1441 ha and whereas Panflora ranged from 20 to 1235 ha. In both sites, home range overlap was practically restricted to pairs of males and females. The deaths of the animals tracked were caused by running over and natural predation, resulting in survival of 26 % in the APMManso and 50 % in Panflora. Of the 19 individuals of M. gouazoubira rescued in APM-Manso, 14 were equipped with transmitters and tracked. The survival was of 60 % and the average distance covered was 11.4 km from the releasing site. The average time to establish home range was 45.6 days, their average size of 111.3 ha and there was no record of overlapping among them.
Efeito da época de coleta, condições de armazenamento, substratos e sombreamento na emergência de plântulas e produção de mudas de Ocotea porosa (Ness et Martius ex. Ness) (Lauraceae) e de Sapindus saponaria L. (Sapindaceae).
(Universidade Federal de São Carlos, 2005-03-21) Tonin, Gláucia Alvarez; Perez, Sonia Cristina Juliano Gualtieri de Andrade; https://lattes.cnpq.br/9973185407856723
ABSTRACT: The knowledgment about techniques for plant propagation is important as a key to recovery degradated areas. In order to get plants high quality it is necessary to harvest seeds wth good vigour and viability, and so, the time with that seeds will harvest produce a significative influence on plant growth. The aim of this work is to add informations about Ocotea porosa (imbuia) and Sapindus saponaria (sabão-desoldado), including the influence of seed moisture level, storage conditions, substractum and luminosity on seedling vigour and viability, as well as in plant growth. O. porosa seeds were harvest with 40% of moisture level, and a half part of this lot is dryed until reaching values of 30%. After, both seed lots were stored at different containners (plastic bags and glasses) and environment (laboratory and cool camera) and during six months. After finished the storage period, the seeds were snowed in different substractum (agricultural substractum and cerrado soil plus sawdust) under full sunlight and 65% of artificial shadding. The seedling rate and emergence percentage were evaluated as well as the plant growth at 270 days after snow. A cluster, graphics and mainly components analysis were done and the results indicated that O. porosa seeds presented the highest vigour and viability when harvest with 40% of moisture level , storaged inside plastic bags, in both environment. The best conditions for plant growth is under 65% of shadding with cerrado soil plus sawdust. The S. saponaria seeds were harvest with 15 and 51% of moisture level, stored in plastic, glasses and cotton bags during six and twelve months. After these periods the seeds were snowed in agricultural substractum, cerrado soil plus sawdust, vermiculita and sand plus cerrado soil. The plant growth under zero and 65% of artificial shadding, and the seedling rate and emergence percentage, and plant growth at 270 days after snowing is also evaluated. The seed vigour and viability were maintened during 12 month, when the seeds were harvested with 15% of moisture level, in a cool camara and inside semipermeable and impermeable containners. The plants presented a best growth under 65% of artificial shadding using agricultural substractum. The storage conditions promoved a reduction of moisture level from 51% to around 20% and these fact affected positively the plant growth.