Fast calcium transients translate the distribution and conduction of neural activity in different regions of a single sensory neuron

Abstract

In the present study, cytosolic calcium concentration changes were recorded in response to various forms of excitations, using the fluorescent calcium indicator dye OG-BAPTA1 together with the current or voltage clamp methods in stretch receptor neurons of crayfish. A single action potential evoked a rise in the resting calcium level in the axon and axonal hillock, whereas an impulse train or a large saturating current injection would be required to evoke an equivalent response in the dendrite region. Under voltage clamp conditions, amplitude differences between axon and dendrite responses vanished completely. The fast activation time and the modulation of the response by extracellular calcium concentration changes indicated that the evoked calcium transients might be mediated by calcium entry into the cytosol through a voltage-gated calcium channel. The decay of the responses was slow and sensitive to extracellular sodium and calcium concentrations as well as exposure to 1-10 mM NiCl and 10-500 µM lanthanum. Thus, a sodium calcium exchanger and a calcium ATPase might be responsible for calcium extrusion from the cytosol. Present results indicate that the calcium indicator OG-BAPTA1 might be an efficient but indirect way of monitoring regional membrane potential differences in a single neuron.

Knockout of zebrafish desmin genes does not cause skeletal muscle degeneration but alters calcium flux

“…On the following day, fibres were incubated in 2.5 μM Fluo-4 AM for 20 min in 5% CO 2 . Under a LSM Pascal laser scanning confocal microscope (Carl Zeiss, Jena, Germany), glass microelectrodes (filled with 3 M KCl) were inserted into muscle fibres in a current clamp mode 38 . A depolarizing current stimulus was delivered through the microelectrode to excite the fibre and evoke a calcium signal.…”

The In Ovo Feeding Administration (Gallus Gallus)—An Emerging In Vivo Approach to Assess Bioactive Compounds with Potential Nutritional Benefits

“…Calcium (Ca 2+ ), is an essential nutrient in the human body; as such, it participates in various biological pathways such as: intracellular metabolism, nerve conduction, blood muscle concentration, bone growth, and skeletal structural support [ 80 , 81 ]. Insufficient calcium uptake will cause bone resorption and the decrease of bone mass, which may lead to metabolic bone diseases, such as rickets in children and osteoporosis in the elderly [ 82 ].…”

Knockout of zebrafish desmin genes does not cause skeletal muscle degeneration but alters calcium flux

“…On the following day, fibres were incubated in 2.5 μM Fluo-4 AM for 20 minutes in 5% CO 2 . Under a laser scanning confocal microscope (Zeiss LSM Pascal), glass microelectrodes (filled with 3M KCl) were inserted into muscle fibres in a current clamp mode 29 . A depolarizing current stimulus was delivered through the microelectrode to excite the fibre and evoke a calcium signal.…”