Hydroid stolonal contractions mediated by contractile vacuoles

Hydroid Stolonal Contractions Mediated by Contractile Vacuoles

The growth and development of colonial hydroids is dependent upon a flow of gastrovascular fluid through a common vasculature. Gastrovascular flow is believed to be driven by polyp contractions, stolonal contractions and endodermal ciliation. In the athecate hydroid Hydr•actinia symbiolongicarpus we found that polyp contractions, stolonal contractions and gastrovascular flow were only weakly co...

The Physiology of Contractile Vacuoles

Contraction of Isolated Contractile Vacuoles from Amoeba Proteus

The contractile vacuole of freshwater protozoa is involved in regulation of cell volume and of intracellular solutes (6, 13, 22) . Despite the longstanding interest in this organelle and knowledge of its functional significance, little is known of the mechanisms of the primary actions of the contractile vacuole, namely, the formation and expulsion of the vacuolar fluid . This report is concerne...

Proton pumps populate the contractile vacuoles of Dictyostelium amoebae

Amoebae of the eukaryotic microorganism Dictyostelium discoideum were found to contain an interconnected array of tubules and cisternae whose membranes were studded with 15-nm-diameter "pegs." Comparison of the ultrastructure and freeze-fracture behavior of these pegs with similar structures found in other cells and tissues indicated that they were the head domains of vacuolar-type proton pumps...

CONTRACTIONS DUE TO α-ADRENOCEPTOR AGONISTS ARE MEDIATED BY α1-ADRENOCEPTORS IN RAT CAROTID ARTERY

Some large vessels have a mixed functional population of postjunctional α1- and α 2-adrenoceptors. The purpose of the work presented here was to investigate the population of postjunctional α -adrenoceptors in the rat isolated common carotid artelY Male Wi star rats were killed by overdose with pentobarbitone sodium, after which the left and right common carotid arteries were removed. Rings...