Search results for "patch-clamp"
showing 10 items of 85 documents
Choline is a Selective Agonist of α7 Nicotinic Acetylcholine Receptors in the Rat Brain Neurons
1998
In the present study, we demonstrate that choline, a precursor of acetylcholine (ACh) and a product of acetylcholine hydrolysis by acetylcholinesterase (AChE), acts as an efficient and relatively selective agonist of alpha7-containing nicotinic acetylcholine receptors (nAChR) in neurons cultured from the rat hippocampus, olfactory bulb and thalamus as well as in PC12 cells. Choline was able to activate postsynaptic and presynaptic alpha7 nAChRs, with the latter action resulting in the release of other neurotransmitters. Although choline was approximately one order of magnitude less potent than ACh (EC50 of 1.6 mM for choline and 0.13 mM for ACh), it acted as a full agonist at alpha7 nAChRs.…
Involvement of purinergic nerves in the NANC inhibitory junction potentials in pigeon oesophageal smooth muscle.
2004
1. Electrical field stimulation (EFS) (0.5 ms in train of 2-32 Hz for 300 ms) in smooth muscle of pigeon oesophagus, in the presence of atropine (1 microm) and guanethidine (1 microm), elicited an inhibitory response consisting of a transient hyperpolarization (inhibitory junction potential, IJP) associated with muscle relaxation. 2. Sodium nitroprusside (SNP, 100 microm) induced hyperpolarization correlated to mechanical relaxation. 3. The nitric oxide (NO) synthase inhibitor N(omega)-nitro-l-arginine (from 0.1 to 100 microm) caused a concentration-dependent reduction of electromechanical response to EFS indicating a role for NO in this response. 4. Apamin (1 microm) reduced both IJP and r…
Neocortical Layer 6B as a Remnant of the Subplate - A Morphological Comparison.
2015
The fate of the subplate (SP) is still a matter of debate. The SP and layer 6 (which is ontogenetically the oldest and innermost neocortical lamina) develop coincidentally. Yet, the function of sublamina 6B is largely unknown. It has been suggested that it consists partly of neurons from the transient SP, however, experimental evidence for this hypothesis is still missing. To obtain first insights into the neuronal complement of layer 6B in the somatosensory rat barrel cortex, we used biocytin stainings of SP neurons (aged 0-4 postnatal days, PND) and layer 6B neurons (PND 11-35) obtained during in vitro whole-cell patch-clamp recordings. Neurons were reconstructed for a quantitative charac…
Lineage-reprogramming of Pericyte-derived Cells of the Adult Human Brain into Induced Neurons
2014
Direct lineage-reprogramming of non-neuronal cells into induced neurons (iNs) may provide insights into the molecular mechanisms underlying neurogenesis and enable new strategies for in vitro modeling or repairing the diseased brain. Identifying brain-resident non-neuronal cell types amenable to direct conversion into iNs might allow for launching such an approach in situ, i.e. within the damaged brain tissue. Here we describe a protocol developed in the attempt of identifying cells derived from the adult human brain that fulfill this premise. This protocol involves: (1) the culturing of human cells from the cerebral cortex obtained from adult human brain biopsies; (2) the in vitro expansio…
Purkinje cell loss and motor coordination defects in profilin1 mutant mice.
2012
Profilin1 is an actin monomer-binding protein, essential for cytoskeletal dynamics. Based on its broad expression in the brain and the localization at excitatory synapses (hippocampal CA3-CA1 synapse, cerebellar parallel fiber (PF)-Purkinje cell (PC) synapse), an important role for profilin1 in brain development and synapse physiology has been postulated. We recently showed normal physiology of hippocampal CA3-CA1 synapses in the absence of profilin1, but impaired glial cell binding and radial migration of cerebellar granule neurons (CGNs). Consequently, brain-specific inactivation of profilin1 by exploiting conditional mutants and Nestin-mediated cre expression resulted in a cerebellar hyp…
Paradoxical effect of increased diastolic Ca(2+) release and decreased sinoatrial node activity in a mouse model of catecholaminergic polymorphic ven…
2012
Background— Catecholaminergic polymorphic ventricular tachycardia is characterized by stress-triggered syncope and sudden death. Patients with catecholaminergic polymorphic ventricular tachycardia manifest sinoatrial node (SAN) dysfunction, the mechanisms of which remain unexplored. Methods and Results— We investigated SAN [Ca 2+ ] i handling in mice carrying the catecholaminergic polymorphic ventricular tachycardia–linked mutation of ryanodine receptor (RyR2 R4496C ) and their wild-type (WT) littermates. In vivo telemetric recordings showed impaired SAN automaticity in RyR2 R4496C mice after isoproterenol injection, analogous to what was observed in catecholaminergic polymorphic ventricul…
Mechanical and electrophysiological effects of cromakalim on the human urinary bladder.
1994
The effects of cromakalim on spontaneous and induced mechanical activity of human detrusor muscle were investigated in vitro. Cromakalim produces a concentration-related decrease of spontaneous as well as carbachol- and K(+)-evoked contractions. This is the first study to utilize the patch clamp technique to elucidate the mechanism of action of cromakalim on human detrusor cells. Cromakalim hyperpolarizes the detrusor cells by increasing the net outward current which is most likely carried by potassium ions. In the human urinary bladder, this effect is mediated by a glibenclamide-sensitive potassium channel, as glibenclamide is able to diminish the relaxant effect of cromakalim and to preve…
Extracellular site of action of phenylalkylamines on L-type calcium current in rat ventricular myocytes.
1995
The effects of the phenylalkylamines verapamil, gallopamil, and devapamil on L-type calcium currents (ICa) were studied in ventricular myocytes from rat hearts using the whole-cell patch-clamp technique. In particular, the question was addressed, whether the pharmacological binding sites for these drugs were located at the inner and/or at the outer surface of the cell membrane. Therefore, tertiary verapamil, gallopamil, and devapamil and their corresponding quaternary derivatives were applied either from the outside or the inside of the cell membrane. Extracellular application of verapamil, gallopamil and devapamil (each at 3 microM) reduced ICa to 16.1 +/- 8.6%, 11 +/- 8.9%, and 9.3 +/- 6%…
Dendrites are dispensable for basic motoneuron function but essential for fine tuning of behavior.
2014
Dendrites are highly complex 3D structures that define neuronal morphology and connectivity and are the predominant sites for synaptic input. Defects in dendritic structure are highly consistent correlates of brain diseases. However, the precise consequences of dendritic structure defects for neuronal function and behavioral performance remain unknown. Here we probe dendritic function by using genetic tools to selectively abolish dendrites in identified Drosophila wing motoneurons without affecting other neuronal properties. We find that these motoneuron dendrites are unexpectedly dispensable for synaptic targeting, qualitatively normal neuronal activity patterns during behavior, and basic …
GABA transporters control GABAergic neurotransmission in the mouse subplate.
2015
The subplate is a transient layer between the cortical plate and intermediate zone in the developing cortex. Thalamo-cortical axons form temporary synapses on subplate neurons (SPns) before invading the cortical plate. Neuronal activity within the subplate is of critical importance for the development of neocortical circuits and architecture. Although both glutamatergic and GABAergic inputs on SPns were reported, short-term plasticity of GABAergic transmission has not been investigated yet. GABAergic postsynaptic currents (GPSCs) were recorded from SPns in coronal neocortical slices prepared from postnatal day 3-4 mice using whole-cell patch-clamp technique. Evoked GPSCs (eGPSCs) elicited b…