Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Electrotonic properties of neostriatal neurons are modulated by extracellular potassium (1988)
    Springer
    Experimental brain research 72 (1988), S. 390-398 
    Details
    ISSN: 1432-1106
    Keywords: Neostriatum ; Neostriatal slices ; Electrotonic properties ; Extracellular potassium ; TEA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to assess the effects of [KK]o on the passive membrane properties of neostriatal neurons, the cable properties of these cells were determined at two extracellular potassium concentrations (6.25 and 3.0 mM). The effect of tetraethylammonium (TEA) on cable properties was also studied at 6.25 [KK]o. At 6.25 mM [KK]o, the mean input resistance at the resting membrane potential (RMP), and the mean membrane time constant (τo) were 27±1.5 MΩ and 6.9±0.5 ms respectively (n=17), while at 3 mM [KK]o they were 62.9±4.8 MΩ and 14.3±0.6 ms (n=15) (mean ±SEM). With one of the methods used to calculate the electronic parameters, the total electrotonic length of the dendrites (L) and the dendritic to somatic conductance ratio (γ) were 1.3±0.05 and 5±0.8 at the higher [KK]o respectively, while they were 0.95±0.04 and 3±0.7 at the lower [KK]o. Cells were depolarized in 6.25 as compared to 3 mM [KK]o (RMP=-66±1.3 mV vs RMP=-80.5±1.4 mV). After one hour exposure to TEA (10 mM), the input resistance and time constant tripled at 6.25 mM [KK]o. TEA slightly depolarized the cells bathed in 6.25 mM [KK]o. The results suggest that changes in [KK]o, within the physiological range, markedly affect the cable properties of neostriatal neurons, possibly modifying subthreshold, voltage-dependent KK-conductances. TEA seems to block some of these channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250260
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The role of calcium in the repetitive firing of neostriatal neurons (1989)
    Springer
    Experimental brain research 75 (1989), S. 157-168 
    Details
    ISSN: 1432-1106
    Keywords: Neostriatum ; Neostriatal slices ; Ca++-activated potassium conductance ; Ca++-blockers ; TEA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Ca++-dependence of the repetitive firing of neostriatal neurons was studied in an in vitro slice preparation of the rat neostriatum. Neuronal firing was evoked by injecting depolarizing currents of 100–200 ms duration. In normal conditions, the mode of firing was tonic and showed very little adaptation. The frequency-current relation was linear over a wide range of frequencies. The repetitive firing was first enhanced and later suppressed by Co++, Mn++ and Cd++. These effects on the repetitive firing by the Ca++-channel blockers paralleled the suppression of the slow afterhyperpolarizing potential. The lowering (0.2 mM) of Ca++ had similar effects. In the presence of TEA (up to 10 mM), the cell fired both Na+ and Ca+ action potentials. The results suggest that, as in other CNS neurons of the vertebrate, in neostriatal neurons the slow afterhyperpolarizing potential (AHP) is due to a Ca++-activated K+-conductance, and that the AHP plays a crucial role in the repetitive firing of these neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248539
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    An early outward conductance modulates the firing latency and frequency of neostriatal neurons of the rat brain (1989)
    Springer
    Experimental brain research 75 (1989), S. 146-156 
    Details
    ISSN: 1432-1106
    Keywords: Neostriatum ; Neostriatal slices ; A-current ; 4-aminopyridine ; TEA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An in vitro slice preparation was used to obtain intracellular recordings of neostriatal neurons. Indirect evidence for the presence of an early outward conductance in neostriatal neurons is presented. With near threshold stimulation neostriatal neurons fired very late during the pulse. The long firing latency was associated with a slow (ramp-like) depolarization. In the presence of TTX the slow depolarization was lost and outward-going rectification dominated the subthreshold response. This finding demonstrated that both, outward and inwardgoing conductances play a role during the ramp-like depolarization. Outward-going rectification during depolarizing responses could be further augmented if the depolarizing stimulus was preceded by a conditioning hyperpolarization. A conditioning hyperpolarization prolonged the firing latency and slowed the firing frequency. A conditioning depolarization had opposite effects. After TTX treatment, the response showed a hyperpolarizing “sag” when depolarizing stimulation was preceded by conditioning hyperpolarization. 4-AP (0.5–2.5 mM) blocked the effects of the conditioning hyperpolarization on the firing latency and on the voltage trajectory. 4-AP also disclosed a slow depolarization which could produce neuronal firing very early during the pulse. This depolarization was TTX-sensitive and Co++-insensitive. In contrast to 4-AP, TEA (20 mM) did not produce a reduction in the firing latency but disclosed a membrane oscillatory behavior most probably produced by the interplay of these opposing conductances: the slow inward (probably Na+) and the transient outward (probably K+). Repetitive firing during 4-AP treatment was of the “phasictonic” type with an initial burst riding on the initial Co++-insensitive slow depolarization and a somehow irregular train of spikes during the remainder of the stimulation. Action potentials during 4-AP treatment were followed by an afterdepolarization which dominated the initial part of the interspike interval.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248538
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...