RESUMO
Chloralose-anesthetised rats were to investigate the blood pressure (BP) responses to electrical stimulation of afferent fibres in the renal nerve. In these rats, stimulation of the proximal end of the cut renal nerve produced either a rapidly reversed fall in BP (at 3V, 5V and 10V) or an initial fall followed by a rise in BP (at 5V and 10V). Dissection of the nerve into two branches and subsequent stimulation yielded a fall in BP by one branch and a rise by the other branch. Also, stimulation of the renal nerve before and after transection at various levels of the medulla oblongata and the spinal cord produced results which indicated that the fall in BP was a bulbar reflex that was integrated at the obex in the medulary region of the brain, but the rise in BP was a spinal reflex that was integrated at a spinal site caudal to the second cervical segment. It is concluded that,in the rat, there are at least two distinct groups of renal afferent fibres which can mediate blood pressures changes that may represent important renal regulatory reflexes.(AU)
Assuntos
Ratos , 21003 , Pressão Arterial , Rim/inervação , Fibras Nervosas , Estimulação ElétricaRESUMO
Muscle tissue obtained by needle biopsy from the quadriceps femoris of eight malnourished and eight recovered children were examined histologically. In both groups about two-thirds of the total nuclear count was due to muscle nuclei. The remaining one-third was made up of vascular, nerve, and interstitial cells and isolated nuclei in similar proportions in the two groups. A significantly greater percentage of muscle nuclei consisted of myogenic cells in recovered children as compared to malnourished children(20.7 ñ 6.4 vs. 2.6 ñ 1.4 percent)(AU)
Assuntos
Humanos , Lactente , Pré-Escolar , Masculino , Feminino , Núcleo Celular/ultraestrutura , Desnutrição Proteico-Calórica/patologia , Vasos Sanguíneos/ultraestrutura , DNA/análise , Músculos/análise , Fibras Nervosas/ultraestrutura , Desnutrição Proteico-Calórica/metabolismoRESUMO
The neck region of the mature spermatozoon of discus rotundatus is described. No evidence for a centriole or centriolar derivative is obtained. Nine striated coarse fibres and the two central fibres of the axoneme extend into the base of the implantation fossa. The axonemal doublet system is disrupted in the neck region. There are two fibrous acessory structures located between the central doublet and the striated coarse fibres (AU)
