title: Intrinsic properties of nucleus reticularis thalami neurones of the rat studied in vitro.
abstract: 1. Neurones of the nucleus reticularis thalami of the rat were studied by intracellular recordings from in vitro slices. The resting membrane potential was -56.28 +/- 5.86 mV (mean value +/- S.D.); input resistance was 43.09 +/- 9.74 M omega; the time constant tau was 16.51 +/- 3.99 ms. At the resting membrane potential tonic firing is present, while at membrane potentials more negative than -60 mV a burst firing mode gradually prevails. 2. Prolonged depolarizing current pulses superimposed on a steady hyperpolarization consistently activated sequences of burst-after-hyperpolarization complexes. The all-or-none burst response consisted of Na+-mediated, TTX-sensitive fast action potentials superimposed on a low threshold spike (LTS). The burst was followed by a stereotyped after-hyperpolarization lasting 100-120 ms (BAHP), with a maxima -85 mV. The BAHP was blocked by Cd2+ and apamine but not by 8-Br cyclic AMP. The early component of BAHP was significantly attenuated by TEA. The oscillatory rhythmic discharges were abolished by agents which blocked the BAHP. 3. The presence of strong after-hyperpolarizing potentials (SAHP and BAHP) in RTN neurones plays a significant role in determining two different functional states, defined as tonic and oscillatory burst firing modes, respectively.
authors.affiliation: Dipartimento di Neurofisiologia, Istituto Neurologico, Besta, Milan, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Avanzini
authors.forename: M
authors.initials: M
authors.lastname: de Curtis
authors.forename: F
authors.initials: F
authors.lastname: Panzica
authors.forename: R
authors.initials: R
authors.lastname: Spreafico
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D002104:Cadmium / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008564:Membrane Potentials; D051381:Rats; D011919:Rats, Inbred Strains; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013787:Thalamic Nuclei / Q000502:physiology*
chemical_list: D013757:Tetraethylammonium Compounds; D002104:Cadmium; D001030:Apamin; D013779:Tetrodotoxin; D019789:Tetraethylammonium; D000242:Cyclic AMP