[Olympus cell R: imaging station for life science].

Modern cell biology makes use of a variety of methods to investigate how cells function. A better knowledge on the cellular machinery opens the door for a better understanding of physiological and pathophysiological interactions. Cellular processes are dynamic; therefore it is necessary to investigate the physiological function and the mode of action of biomolecules, as well as the interaction of biomolecules.

Arachidonic acid in astrocytes blocks Ca(2+) oscillations by inhibiting store-operated Ca(2+) entry, and causes delayed Ca(2+) influx.

ATP-elicited oscillations of the concentration of free intracellular Ca(2+) ([Ca(2+)](i)) in rat brain astrocytes were abolished by simultaneous arachidonic acid (AA) addition, whereas the tetraenoic analogue 5,8,11,14-eicosatetraynoic acid (ETYA) was ineffective. Inhibition of oscillations is due to suppression by AA of intracellular Ca(2+) store refilling. Short-term application of AA, but not ETYA, blocked Ca(2+) influx, which was evoked by depletion of stores with cyclopiazonic acid (CPA) or thapsigargin (Tg).

Thrombin (PAR-1)-induced proliferation in astrocytes via MAPK involves multiple signaling pathways.

Protease-activated receptors (PARs), newly identified members of G protein-coupled receptors, are widely distributed in the brain. Thrombin evokes multiple cellular responses in a large variety of cells by activating PAR-1, -3, and -4. In cultured rat astrocytes we investigated the signaling pathway of thrombin- and PAR-activating peptide (PAR-AP)-induced cell proliferation.

Arachidonic acid and docosahexaenoic acid suppress thrombin-evoked Ca2+ response in rat astrocytes by endogenous arachidonic acid liberation.

Arachidonic (AA) and docosahexaenoic acid (DHA) are the major polyunsaturated fatty acids (PUFAs) in the brain. However, their influence on intracellular Ca2+ signalling is still widely unknown. In astrocytes, the amplitude of thrombin- induced Ca2+ response was time-dependently diminished by AA and DHA, or by the AA tetraynoic analogue ETYA, but not by eicosapentaenoic acid (EPA).

Human bronchial epithelial cells express PAR-2 with different sensitivity to thermolysin.

Protease-activated receptor-2 (PAR-2) plays a role in inflammatory reactions in airway physiology. Proteases cleaving the extracellular NH(2) terminus of receptors activate or inactivate PAR, thus possessing a therapeutic potential. Using RT-PCR and immunocytochemistry, we show PAR-2 in human airway epithelial cell lines human bronchial epithelial (HBE) and A549.