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Ca(v)1.3 (alpha 1D) L-type Ca(2+) channels have been implicated in substantia nigra (SN) dopamine (DA) neuron pacemaking and vulnerability to Parkinson's disease. These effects may arise from the depolarizing current and cytoplasmic Ca(2+) elevation produced by Ca(v)1.3 channels at subthreshold membrane potentials. However, the assumption that the Ca(2+)(More)
The dynamic-clamp method provides a powerful electrophysiological tool for creating virtual ionic conductances in living cells and studying their influence on membrane potential. Here we describe G-clamp, a new way to implement a dynamic clamp using the real-time version of the Lab-VIEW programming environment together with a Windows host, an embedded(More)
1. Post-ganglionic neurones of the rat superior cervical ganglion were studied in vitro (21-26 degrees C) using single intracellular micro-electrode methods. 2. Three Ca2+-dependent potentials were studied: the shoulder on the normal action potential, the hyperpolarizing afterpotential (h.a.p.), and th Ca2+ spike. 3. Bath-applied noradrenaline reversibly(More)
Norepinephrine reversibly antagonizes three calcium-dependent potentials recorded from rat postganglionic neurons. Norepinephrine inhibits the development of a shoulder on the aciton potential, the magnitude of the hyperpolarizing afterpotential, and the rate of rise and amplitude of the calcium spike. The action of norepinephrine is antagonized by the(More)
1. The cellular organization of the ninth and tenth paravertebral sympathetic ganglia in the bullfrog was studied with intracellular and extracellular recording methods. An isolated preparation was used in which anatomical details of individual cells could be resolved while making physiological measurements. This permitted the characterization of neurones(More)
These experiments were designed to characterize the distribution, morphology, and number of spinal preganglionic neurons that selectively innervate the B- and C-type sympathetic neurons in paravertebral ganglia 9 and 10 of the bullfrog. For this purpose, horseradish peroxidase (HRP) was applied to the anterior end of the sectioned sympathetic chain between(More)
The strength and number of nicotinic synapses that converge on secretomotor B neurons were assessed in the bullfrog by recording intracellularly from isolated preparations of paravertebral sympathetic ganglia 9 and 10. One input to every B neuron invariably produced a suprathreshold EPSP and was defined as the primary nicotinic synapse. In addition, 93% of(More)
A new scheme is presented for identifying three sympathetic phenotypes in the rat superior cervical ganglion using electrophysiology and neuropeptide Y expression. Postganglionic compound action potentials recorded from the external and internal carotid nerves each contained two peaks, 1 and 2, with distinct preganglionic stimulus thresholds. Peak 2 in the(More)
The predominant form of muscarinic excitation in the forebrain and in sympathetic ganglia arises from m1 receptors coupled to the G(q/11) signal transduction pathway. Functional components of this system have been most completely mapped in frog sympathetic B neurons. Presynaptic stimulation of the B neuron produces a dual-component muscarinic excitatory(More)
Electrophysiological approaches using intracellular microelectrode techniques have failed to critically test the hypothesis that cyclic AMP (cAMP) mediates the slow inhibitory postsynpatic potential (IPSP). The slow IPSP is not readily elicited, and the resting membrane potential is relatively insensitive to application of catecholamines and adenine(More)