1. The adenosine analogue 2-chloroadenosine (CADO) reduced the duration of calcium-dependent action potentials (CAPs) in mouse dorsal root ganglion (DRG) neurones in culture, by reducing voltage-activated calcium conductance (Macdonald, Skerritt & Werz, 1986). Using the single-electrode voltage clamp technique, we recorded three calcium current components in these neurones, the transient low-th...

background: calcium is the most abundant mineral in the human body. this mineral is provided only by the consumption of foods containing calcium that it is recommended to use at least1300 mg daily for adults. this study is aimed to investigate the nutritional behavior of female high school students about consumption of calcium-rich foods.materials and methodsat a descriptive-analytical study, t...

Slow ionic currents were measured in the rat omohyoid muscle with the three-microelectrode voltage-clamp technique. Sodium and delayed rectifier potassium currents were blocked pharmacologically. Under these conditions, depolarizing test pulses elicited an early outward current, followed by a transient slow inward current, followed in turn by a late outward current. The early outward current ap...

Giant synaptic terminals (approximately 10 micrometer diameter) of bipolar neurons from goldfish retina were used to directly investigate calcium-dependent inactivation of presynaptic calcium current. During sustained depolarization, calcium current was initially constant for a period lasting up to several hundred milliseconds and then it declined exponentially. The duration of the initial dela...

Marine sponges are synthesizing a wide variety of peptidic and organic molecules with biological activities. Multiple-step purification of Cliona vastifica extract led to a new dimeric peptide (mapacalcine; M(r) = 19,064) that is composed of two homologous chains, each containing nine cysteins. This protein has been found to selectively block a new calcium conductance characterized in mouse duo...

White bass (Roccus chrysops) retinal horizontal cells possess two types of voltage-activated calcium currents which have recently been characterized with regard to their voltage dependence and pharmacology (Sullivan, J., and E. M. Lasater. 1992. Journal of General Physiology. 99:85-107). A low voltage-activated transient current was identified which resembles the T-type calcium current describe...

Outward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca(2+)-dependent K+ currents (IKCa) probably correlated with variations in intracellular Ca2+ concentration. Addition of external Na+ (8 mM) immediately abol...

Fluctuation analysis is a method that allows measurement of the single-channel current of ion channels even when it is too small to be resolved directly with the patch-clamp technique. This is the case for voltage-gated calcium channels. They are present in all mammalian central neurons, controlling presynaptic release of transmitter, postsynaptic signaling, and synaptic integration. The amplit...