Atrial muscle fibers of the guinea pig were depolarized and rendered inexcitable by elevation of [K + ] o to 22 mM. Isoproterenol, epinephrine, and norepinephrine restored propagated action potentials and contractions to atrial cells without changing the resting potential. The peak value of the intracellularly recorded action potentials varied 28 mv for a 10-fold change in [Ca + ]0 . Isoprotere...

The electrophysiological properties of a tissue culture muscle line, L6, and a K+ resistant mutant (MK1) derived from L6 were determined to elucidate certain aspects of membrane differentiation and function. MK1 was selected as a clone of myoblasts resistant to the toxic effects of 55 mM K+. The resting potentials of L6 and MK1 myoblasts and myotubes were K+ dependent and equal. The amplitudes ...

To investigate the influence of brain mediated functions on control of ocular growth, young chicks were treated monocularly with intravitreally injected tetrodotoxin (TTX) to block retinal ganglion cell action potentials. TTX injections (0.7 micrograms in 7 microliters) were given on day 6 after hatching in both binocularly open and monocularly deprived chicks. Injections were repeated every 48...

In the mammalian cortex, it is generally assumed that the output information of neurons is encoded in the number and the timing of action potentials. Here, we show, by using direct patchclamp recordings from presynaptic hippocampal mossy fiber boutons, that axons transmit analog signals in addition to action potentials. Excitatory presynaptic potentials result from subthreshold dendritic synapt...

Taste cells regularly generate action potentials, but their functional significance in taste signaling is unclear. A paper in BMC Neuroscience reveals the identity of the voltage-gated Na+ channels underlying action potentials, providing the foundation for insights into their function.

We examined relations between cellular currents activated near firing threshold and the initiation of action potentials by excitatory postsynaptic potentials (EPSPs) in CA1 pyramidal cells in vitro. Small voltage steps elicited sequences of inward-outward currents at hyperpolarized potentials, but evoked largely inward currents at near threshold potentials. Similarly small EPSP-like waveforms i...

2003;548;745-752; originally published online Mar 14, 2003; J. Physiol. Morten Raastad and Gordon M. G. Shepherd Single-axon action potentials in the rat hippocampal cortex This information is current as of April 14, 2008 publication unless article is open access. This version of the article may not be posted on a public website for 12 months after http://jp.physoc.org/cgi/content/full/548/3/74...

Voltage-elicited action potentials (APs) have been reproducibly obtained in Arabidopsis thaliana ecotype col. Excitations pulses (voltage-duration: V-t) were given in the 0- to 18-V and 0- to 35-s ranges, respectively, by two galvanically isolated Pt/Ir small wires inserted trough the main vein in the distal part of the leaf. Conventional liquid junction Ag/AgCl electrodes were placed at the zo...

The understanding of neuronal circuits has been, and will continue to be, greatly advanced by the simultaneous imaging of action potentials in neuronal ensembles. This protocol describes "bulk" loading of brain slices with acetoxymethyl (AM) ester calcium indicators in order to monitor action potential activity in large populations of neurons simultaneously. The imaging of calcium influx into n...

SPEAK, JOSEPH F., AND E. NEIL MOORE. A comparison of alternation in myocardial action potentials and contractility. Am. J. Physiol. 220(6): 1708-1716. 197 1 .-The transmembrane potentials and isometric force of contraction were simultaneously recorded from the isolated papillary muscles of the cat, rabbit, guinea pig, and rat right ventricles, and from frog ventricular trabeculae. The pattern o...