Adrenal chromaffin cells, catecholamine detection

Acridine orange DNA binding, 45 use in DNA intercalation, 44-58 Adrenal chromaffin cells, catecholamine detection, 75,77,78/... 

Permeabilized secretory cells are widely used to study the final events during secretion by exocytosis. Convenient cellular models are bovine adrenal chromaffin cells in short term culture and the rat pheochromocytoma cell line PC 12. Both cell types take up labeled catecholamines and store them in secretory vesicles, from which they can be released upon stimulation. The released catecholamines can be detected in the supernatant. After permeabilization of the plasma membrane, release of catecholamines can be triggered by micromolar concentrations of Ca. ... 

Owing to the broad spectrum of substrates for both enzymes, the sensor responds to various catecholamines, aminophenols and ferrocene derivatives. The best sensitivities were obtained for aminophenol and epinephrine where the lower limit of detection is 100 pM. The recycling sensor was used to trace the secretion of catecholamines in cultures of adrenal chromaffin cells. Furthermore both a sandwich assay for IgG and displacement of enzyme labeled cocaine have been indicated by the amplification enzyme sensor. 

Detection of catecholamines from adrenal chromaffin cells... 

Figure 14 Experiments with a carbon fiber electrode at a single adrenal chromaffin cell exposed to 50 pM histamine for 5 s (indicated by the long bar). A 3 s exposure to a solution containing 100 nM Ca + and 50 pM epinephrine was used to postcalibrate the microsensor (shown by the short bar). In panel A, release from a single cell was evoked by histamine exposure and resulted in the amperometric spikes due to catecholamine oxidation (lower panel). At the same time, Ca release was detected. In panel B, neither catecholamine nor Ca - release was detected from a single cell after histamine exposure. I is the fluorescence intensity. Data were obtained using a 5pm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from Anal. Client, with permission [45].)...

Pitta Bauermann et al. have applied constant distance shear force-controlled SECM to elec-trochemically image fibroblasts and adrenal chromaffin ceUs. In the case of the catecholamine-releasing chromaffin cells, the authors succeeded in amperometrically detecting the release of neurotransmitters from a single secretory vesicle, following chemical stimulation. 

---