The Hydra head activator in human blood circulation

Tentacle morphogenesis in hydra I. The role of head activator

Stimulation of tentacle-specific cell differentiation by the neuropeptide head activator was investigated in Hydra magnipapillata. Tentacle-specific sensory nerve cells were identified by a monoclonal antibody, NV1. Treatment of hydra with 1 pM head activator for 18 h stimulated differentiation of NV1 nerve cells and tentacle epithelial cells in tissue from the distal gastric region. Head tissu...

Role of the neuropeptide head activator for growth and development in hydra and mammals.

In hydra, HA is produced by nerve cells and released into the intercellular space bound to large-molecular-weight carrier(s). By additional interaction with extracellular matrix components and selfinactivation by dimerisation, a local action is ensured. HA acts as a mitogen on all dividing cell types in hydra forcing them to pass through G2, divide, and either start a new round of cell division...

A head-activator binding protein is present in hydra in a soluble and a membrane-anchored form.

The neuropeptide head activator plays an important role for proliferation and determination of stem cells in hydra. By affinity chromatography a 200 kDa head-activator binding protein, HAB, was isolated from the multiheaded mutant of Chlorohydra viridissima. Partial amino acid sequences were used to clone the HAB cDNA which coded for a receptor with a unique alignment of extracellular modules, ...

Circulation of the blood

Head movement, an important contributor to human cerebrospinal fluid circulation

The suboccipital muscles are connected to the upper cervical spinal dura mater via the myodural bridges (MDBs). Recently, it was suggested that they might work as a pump to provide power for cerebrospinal fluid (CSF) circulation. The purpose of this study was to investigate effects of the suboccipital muscles contractions on the CSF flow. Forty healthy adult volunteers were subjected to cine ph...