Using single rat adrenal chromaffin cells, we examined the coupling of action potential activity to quantal release of catecholamines by combining perforated patch current-clamp recording with electrochemical microcarbon fiber amperometry. Chromaffin cells display steeper dependence of quantal release on action potential frequency than many nerve terminals, as well as more desynchronized release following an action potential. Also in contrast to neurons, in chromaffin cells, a major chemical secretagogue (acetylcholine) triggers potent quantal release even in the absence of electrical activity. These findings are consistent with an hypothesis that a major component of exocytosis from chromaffin cells involves diffusion of Ca2+ to secretion sites which are less well co-localized with Ca2+ channels than those in nerve terminals.
The
Fe3O4@SiO2 paramagnetic Janus particles
with phenyl groups and amino groups segmented on two different sides
were fabricated by the Pickering emulsion method. Then, the poly(ionic
liquid)s were selectively modified onto the amino side via in situ
induced ATRP polymerization. Different anions were introduced onto
the poly(ionic liquid)s region by exchanging anions to adjust the
wettability of the side. Meanwhile, after the PW12O40
3– anions were employed, the poly(ionic
liquid)-modified Fe3O4@SiO2 Janus
particles can be used as a catalytic solid emulsifier and degraded
water-soluble dyes with the aid of stabilizing emulsion.
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