Mild dystrophic damage in the androgen-sensitive levator ani muscle of the mdx mouse.

The time course of muscular dystrophy on the androgen-sensitive levator ani muscle was compared to that of the diaphragm of dystrophic (mdx) mice aged 1-20 months. Muscle growth, isometric contractile properties and caffeine-induced contractures were determined to assess the hormone myotrophic effect, muscle strength and sarcoplasmic reticulum function, respectively, of both control and dystrophic muscles. Histological analysis of mdx muscles showed variable fiber size, centronucleated cells, infiltration of connective tissue, and necrosis which was less severe in the levator ani than in the diaphragm muscle. Tetanic tension per unit weight in the mdx levator ani was reduced (29%) after aging, while the contraction time remained unchanged. The tetanic tension of the mdx diaphragm muscle decreased with age from 3 to 20 months (20-64%), and the relaxation time was prolonged after aging (22%). Gonadectomy of young adult mdx mice caused atrophy of the levator ani muscle, accelerated muscle wasting, reduced the tetanic force (31%), but it did not affect the contraction time and caffeine responses. The results showed that testosterone does not prevent the progress of muscle disease in the mdx levator ani, but androgen withdrawal accelerates muscle wasting suggesting a normonal beneficial effect.

Evaluation of estrogenic receptors in the nasal mucosa of women taking oral contraceptives.

BACKGROUND: There is evidence that the nasal mucosa is affected by estrogen influence. Some authors have already detected estrogen receptors (ER) in the nasal mucosa. However, there doesn't seem to be a consensus about the concentration and distribution of the ER or the possible influence of hormonal contraceptives in the nasal mucosa. OBJECTIVE: The study was conducted to evaluate the influence of oral contraceptives on the distribution and concentration of estrogenic receptors in nasal mucosa. STUDY DESIGN: Two groups of 32 women with regular menstrual cycles were selected. One group of women was taking oral contraceptives and the other was not. Samples of mucosa of inferior nasal turbinate were analyzed by immunohistochemical staining for alpha and beta ER. RESULTS: The use of oral contraceptives induced a decrease of beta-receptors only in lamina propria cells. In both groups, there was a predominance of beta-receptors. CONCLUSION: Women who took oral contraceptives showed a decrease of beta-receptors in some cells of the lamina propria. These findings show us the possibility of effects of contraceptive pills on the cells such as fibroblasts, mast cells, plasmocytes, and other inflammatory cells.

Chronic effects of angiotensin-converting enzyme inhibition on kinin receptor binding sites in the rat spinal cord.

With the use of in vitro receptor autoradiography, this study aims at determining whether the higher level of kinin B(2) receptor density in the spinal cord of the spontaneously hypertensive rat (SHR) is secondary to arterial hypertension and whether chronic treatment with angiotensin I-converting enzyme inhibitors (ACEI) can regulate neuronal B(1) and B(2) receptors. SHR received, from the age of 4 wk, one of the two ACEI (lisinopril or zofenopril, 10 mg x kg(-1) x day(-1)) or for comparison, the selective AT(1) antagonist (losartan, 20 mg x kg(-1) x day(-1)) in their drinking water for a period of 4, 12, and 20 wk. Age-matched untreated SHR and Wistar-Kyoto rats (WKY) were used as controls. B(2) receptor binding sites in most laminae were higher in SHR than in WKY from the age of 8 to 24 wk. Whereas B(1) receptor binding sites were significantly present in young SHR and WKY, they were barely detectable in adult rats. ACEI (16 and 24 wk) and AT(1) antagonist (24 wk) enhanced the number of B(2) without changing B(1) receptor binding sites. However, at 8 wk the three treatments significantly increased B(1) and decreased B(2) receptors in lamina I. It is concluded that 1) the higher density of B(2) receptors in the spinal cord of SHR is not due to hypertension, 2) kinin receptors are regulated differently by ACEI in neuronal and vascular tissues, and 3) aging may have a profound impact on levels of B(1) and B(2) receptors in the rat spinal cord.

Inter-relaçäo eletrofisiológica e neuroanatômica do núcleo paratrigeminal com estruturas bulbares envolvidas no controle da pressäo arterial / Eletrophysiological and neuroanatomical interactions between the paratrigeminal nucleus and medullary structures involved in the arterial blood pressure control

Recentemente foi demonstrado que o Pa5 possui um papel na mediação do efeito pressor a BK injetada na região dorso-lateral do bulbo de ratos não anestesiados, agindo através de receptores do tipo B2. Esta resposta pressora tem origem central e é acompanhada por um moderado aumento da freqüência cardíaca, proveniente de uma estimulação simpática central. Efeito semelhante pode ser obtido por microinjeções de substância P, L-glutamato ou ibotenato no Pa5, sugerindo uma ação excitatória da BK sobre os neurônios do Pa5. O Pa5 possui um grande número de projeções para a área peribraquial, descrita em ratos. Em adição a estes dados, foram sugeridas projeções para os núcleos do trato solitário, reticular lateral e formação reticular de ratos. As projeções do Pa5 para o NTS e área peribraquial sugerem que este núcleo esteja envolvido em processos regulatórios vegetativos e termosensoriais. Resultados deste laboratório demonstraram a presença de eferências bilaterais do Pa5 para o NTS comissural e intermediário, e para a área pressora bulbar rostral ventral lateral. Apesar destes dados obtidos com o uso de traçadores retrógrados indicarem as possíveis áreas de projeção, eles possuem um valor limitado para uma identificação precisa das projeções para pequenas estruturas. O presente estudo determinou as áreas de projeções do Pa5 para o NTS e RVLM, com o uso de traçador de transporte anterógrado, e o envolvimento eletrofisiológico do Pa5 com estas estruturas através de um sistema de registro simultâneo de múltiplos neurônios. O traçador anterógrado biocetina microinjetado no Pa5 proveu uma detalhada imagem das projeções bilaterais do núcleo para o trato solitário, na mesma porção do NTS que recebe as aferências dos baroreceptores, receptores cardiopulmonares e quimioreceptores. As projeções do Pa5 para a medula ventral lateral mostraram uma distinta organização topográfica. No sentido rostral, terminais sinápticos marcados foram observados, em ordem sequencial, no LRt, Amb, na parte rostral do Amb e no RVL, e somente no RVL. A análise eletrofisiológica foi realizada em 112 neurônios do NTS e em 81 neurônios da RVLM após o estímulo do Pa5 por BK e injeção de PHE, S-HT, SNP e KCN iv, e em 74 neurônios do Pa5 após a aplicação de BK sobre o mesmo. Após a aplicação de bradicinina sobre o Pa5 de ratos anestesiados foram registrados 57 neurônios (74 por cento) que aumentaram a freqüência de disparos após a aplicaçäo do peptídio, indicando uma açäo..(au)