Length-weight relationship of fish species from Central Amazon floodplain

Length-weight relationship (LWR) for 39 freshwater fish species captured in the Catalão Lake, a floodplain area at the confluence of the Amazonas and Negro rivers is presented. LWRs were calculated based on fish sampled over 18 years (1999–2017) using a set of ten gill nets with different mesh sizes, monthly immersed in water for 24-hr with 6-hr interval catches. Measurements were done for standard length (SL – 0.1 cm precision) and total weight (TW – 0.01 g precision). The LWRs were calculated by the linear regression of natural log-transformed SL and TW data: TW = a × SL^b. All statistical analyses were performed with R software. From all species considered, 32 are new LWR records for the international literature as well as for the Amazonian ichythyofauna; additional records expand the known size range for seven species.     

P2Y<Subscript>1</Subscript>receptor switches to neurons from glia in juvenile versus neonatal rat cerebellar cortex

Background  

In the CNS, several P2 receptors for extracellular nucleotides are identified on neurons and glial cells to participate to neuron-neuron, glia-glia and glia-neuron communication.     

Comparative study of Mm. Multifidi in lumbar and thoracic spine.

Imbalance of Mm. Multifidi may play a role in spinal disorders such as scoliosis in the thoracic spine, and lumbar disc herniation and lower back pain in the lumbar spine. Even though changes in these muscles are related to the etiology of these disorders, their anatomy is still poorly understood, especially in the upper regions of the spine. With the aim of gaining a better understanding of the anatomy of Mm. Multifidi in the lumbar and thoracic spine, 12 fresh and two embalmed cadavers were dissected. Our results indicate that Mm. Multifidi present differences in lumbar and thoracic spines concerning their deepness, fibre trajectory, muscle length, muscle mass and tendinous tissue. In the lumbar spine Mm. Multifidi are a superficial, thick and fleshy mass, and their fibres are more vertical in relation to the spinous processes. In the thoracic spine Mm. Multifidi are deeper, thinner, and their fibres are more tendinous and oblique than in the lumbar spine. These differences have implications on Mm. Multifidi architecture and consequently for their function in these two regions of the spine.