Learn More
Receptors for excitatory amino acids in the mammalian central nervous system are classified into three major subtypes, ones which prefer N-methyl-D-aspartate (NMDA), quisqualate (QA), or kainate (KA) as type agonists respectively. These receptors are considered to mediate fast postsynaptic potentials by activating ion channels directly (ionotropic type).(More)
Microinjection of mRNA from adult rat brains into Xenopus oocytes induced an electrophysiological response to acetylcholine in the cells. The cells responded to acetylcholine through muscarinic receptors which appeared on the cell surface after microinjection of the mRNA and showed the depolarization, mainly due to an increase in membrane permeability to Cl(More)
Microinjection of rat brain mRNA in Xenopus oocytes induced acetylcholine, neurotensin, serotonin, and glutamate receptors in the cells. These receptors stimulate an intracellular reaction pathway, including G-protein activation, inositol trisphosphate (IP3) formation, and Ca2+-dependent Cl- channels. In the present study, we examined the roles of several(More)
Isoproterenol (IPR) and 8-(4-chlorophenylthio)-cyclic AMP (cpt-cAMP) enhanced carbachol (CCh)-induced fluid secretion from rat parotid glands, but had no effect by themselves. The enhancement by IPR was blocked by propranolol. In dispersed parotid acinar cells, IPR and cpt-cAMP potentiated CCh-induced K+ and Cl- currents (IK and ICl). IPR at the(More)
Elevations of cytoplasmic free calcium concentrations ([Ca(2+)](i)) evoked by cholinergic agonists stimulate isotonic fluid secretion in salivary acinar cells. This process is driven by the apical exit of Cl(-) through Ca(2+)-activated Cl(-) channels, while Cl(-) enters the cytoplasm against its electrochemical gradient via a loop diuretic-sensitive(More)
Xenopus oocytes in which poly(A)+ mRNA isolated from rat brains were previously injected, exhibited at least 3 categories of current responses to excitatory amino acids. They were oscillatory responses to glutamate (Glu) or quisqualate (QA), smooth large responses to kainate (KA), and smooth small responses to Glu and QA. Oscillatory responses were mediated(More)
1. The intracellular reaction mechanism underlying electrophysiological responses evoked by neurotensin (NT) was studied using Xenopus laevis oocytes injected with poly (A)+ messenger ribonucleic acid (mRNA) isolated from rat brains. 2. A few days after the injection of mRNA, oocytes were found to acquire sensitivity to NT and substance P. 3. Under(More)
When Xenopus laevis oocytes were microinjected with poly(A)+ mRNA isolated from adult rat brains or electric organs of Electrophorus electricus, the oocytes developed functional sodium channels. Upon application of veratrine, the microinjected oocytes exhibited transient depolarization, resulting in spontaneous repetitive spikes in some occasions, and(More)
The effects of muscarinic and beta-adrenergic agonists on Cl(-) currents in acinar cells were investigated to clarify their role in the regulation of fluid secretion in rat perfused submandibular glands. Additions of isoproterenol (IPR) at 10(-8) to 10(-6) M and 8-(4-chlorophenylthio)-cyclic AMP (CPT-cAMP) at 10(-3) M to the perfusate suppressed carbachol(More)
Effects of cytochalasin D on actin filaments in cells encircling taste pores were examined to clarify the functional role of actin filaments in the maintenance of taste pores in rat fungiform papillae, using a confocal laser microscope and a scanning electron microscope. Fluorescence in the taste pore cells was detected as a ring shape produced by actin(More)