We used 2',7'-bis(carboxyethyl)-5(6)-carboxyflourescein (BCECF), a pH-sensitive fluorescent dye, to study intracellular pH (pH(i)) regulation in neurons in CO(2) chemoreceptor and nonchemoreceptor regions in the pulmonate, terrestrial snail, Helix aspersa. We studied pH(i) during hypercapnic acidosis, after ammonia prepulse, and during isohydric hypercapnia. In all treatment conditions, pH(i) f...

We have used quartz Ca2+-sensitive microelectrodes (CASMs) in large voltage-clamped snail neurones to investigate the inward spread of Ca2+ after a brief depolarisation. Both steady state and [Ca2+]i transients changed with depth of penetration. When the CASM tip was within 20 microm of the far side of the cell the [Ca2+]i transient time to peak was 4.4+/-0.5s, rising to 14.7+/-0.7s at a distan...

Calf thymus histories comprising two fractions, one rich in lysine, the other having roughly equal amounts of lysine and arginine, Loligo testes histones rich in arginine, and salmine, are compared with respect to their amino acid compositions, and their staining properties when the proteins are fixed on filter paper. The three types of basic proteins; somatic, arginine-rich spermatid histones,...

The schedule of spermatogenesis is determined from the times necessary for cells labeled with tritium thymidine during premeiotic DNA synthesis to pass through the successive spermatogenic stages. A transition from a typically somatic histone rich in lysine, to a histone rich in arginine is shown to occur during spermatid stages. A later shift to a protamine is observed in the maturing sperm. T...

introduction: pentylenetetrazol (ptz) is one of the most often used epileptogenic agents. several effects of this epileptogenic drug have been described, but the mechanism of the epileptogenic action of ptz at the cellular level is still unclear. in this study the effect of ptz, on the ionic currents of d5 neuronal soma membrane in helixaspersa, using intracellular recording technique was inves...

introduction: the functional effects of orexin-b on the calcium spikes and excitability of the neuronal soma membrane of garden snail, helix aspersa were studied. methods: conventional intracellular recording, under the current clamp conditions was performed to examine the effects of orexin-b on the configuration and electrophysiological properties of calcium spikes. results: application of ore...

introduction: some dental sealers have neurotoxic effects on neuronaltissues. these effects appear to be mediated through the inhibition of ionic channels. intracellular recording was performed on neuronal cells tocharacterize the underlying ionic mechanisms of neurotoxicity induced by roth 801. materials and methods: experiments were carried out on f1 neuronal soma membrane located in the righ...

Cells isolated from the hepatopancreas of the land snail Helix aspersa strongly depress respiration both immediately in response to lowered P(O2) (oxygen conformation) and, in the longer term, during aestivation. These phenomena were analysed by dividing cellular respiration into non-mitochondrial and mitochondrial respiration using the mitochondrial poisons myxothiazol, antimycin and azide. No...

Spermatids of the snail Helix aspersa were studied after fixation in buffered osmium tetroxide and after applying Novikoff and Goldfischer's method (15) for demonstrating thiamine pyrophosphatase (TPPase) activity both with the light and the electron microscope. The appearance of cells in the light microscope after localizing the enzyme is very similar to the appearance after the application of...