ABSTRACT
The presence of a complete set of cholinergic molecules, including acetylcholine (ACh) receptors, show the presence of a cell communication system, displaying cholinergic functions. Cholinesterase (ChE) activities were found during sea urchin gastrulation in non-neuromuscular cells and tissues (Drews, 1975), and their presence was considered as a marker for a cholinergic system, regulating developmental cell interactions. To check if this may be considered as a general feature of interacting cells and tissues, the localization of cholinergic molecules was investigated in sperms and eggs of Paracentrotus lividus, by use of cytochemical (Karnovsky and Roots, 1964) method for ChE and indirect immunofluorescence method for ACh- and cholinacetyltransferase (ChAT)-like molecules, by use of polyclonal antibodies obtained respectively from Biosys, F and Chemicon, USA. An indication for the presence of ACh receptors was given by use of alpha-bungarotoxin binding at a concentration (10 uM) that is not discriminant between nicotinic and muscarinic ones. Controls of specificity were performed as usually. The nuclear dynamics of gametes and early embryos were followed by the DAPI (4’,6 - diamidino-2-phenylindole, Sigma USA) staining.
