Synaptic control of excitability in turtle cerebellar Purkinje cells.
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Synaptic control of excitability in turtle cerebellar Purkinje cells. / Hounsgaard, J.; Midtgaard, J.
In: The Journal of Physiology, Vol. 409, No. 1, 01.02.1989, p. 157-170.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Synaptic control of excitability in turtle cerebellar Purkinje cells.
AU - Hounsgaard, J.
AU - Midtgaard, J.
PY - 1989/2/1
Y1 - 1989/2/1
N2 - 1. In turtle Purkinje cells in vitro successive climbing fibre responses (CFRs) gradually induced a hyperpolarization that persisted with maintained stimulation and decayed over minutes after climbing fibre stimulation was terminated. 2. The rate of development and the amplitude of this long‐lasting hyperpolarization (LHP) increased with the frequency of CFRs. 3. The LHP was also induced by Ca2+ spikes evoked by current injection but not by Na+ spikes. The LHP was blocked by Co2+ but not by tetrodotoxin and could not be explained solely by an increased K+ conductance. 4. Depolarizing current during a train of CFRs enhanced the regenerative component of CFRs and promoted the LHP. Hyperpolarizing current during the stimulus train reduced the regenerative component of CFRs and attenuated the resulting LHP. 5. In the range of membrane potentials attained at different levels of climbing fibre activity the regenerative component of CFRs varied from being dominant at very low stimulus frequency (0.1 s‐1) to being inconspicuous at high stimulus frequency (10 s‐1). 6. It is concluded that successive CFRs induce a Ca2+‐dependent, long‐lasting hyperpolarization. The magnitude of the hyperpolarization is regulated by the rate of CFRs and by the voltage‐ and frequency‐dependent configuration of each individual CFR. 7. The active, non‐synaptic properties of turtle Purkinje cells make the Ca2+ influx during climbing fibre responses prone to regulation by on‐going synaptic activity and by the after‐effects of synaptic activity on a time scale of minutes. We suggest that this arrangement may enhance the capacity and complexity of spatial and temporal synaptic integration in Purkinje cells.
AB - 1. In turtle Purkinje cells in vitro successive climbing fibre responses (CFRs) gradually induced a hyperpolarization that persisted with maintained stimulation and decayed over minutes after climbing fibre stimulation was terminated. 2. The rate of development and the amplitude of this long‐lasting hyperpolarization (LHP) increased with the frequency of CFRs. 3. The LHP was also induced by Ca2+ spikes evoked by current injection but not by Na+ spikes. The LHP was blocked by Co2+ but not by tetrodotoxin and could not be explained solely by an increased K+ conductance. 4. Depolarizing current during a train of CFRs enhanced the regenerative component of CFRs and promoted the LHP. Hyperpolarizing current during the stimulus train reduced the regenerative component of CFRs and attenuated the resulting LHP. 5. In the range of membrane potentials attained at different levels of climbing fibre activity the regenerative component of CFRs varied from being dominant at very low stimulus frequency (0.1 s‐1) to being inconspicuous at high stimulus frequency (10 s‐1). 6. It is concluded that successive CFRs induce a Ca2+‐dependent, long‐lasting hyperpolarization. The magnitude of the hyperpolarization is regulated by the rate of CFRs and by the voltage‐ and frequency‐dependent configuration of each individual CFR. 7. The active, non‐synaptic properties of turtle Purkinje cells make the Ca2+ influx during climbing fibre responses prone to regulation by on‐going synaptic activity and by the after‐effects of synaptic activity on a time scale of minutes. We suggest that this arrangement may enhance the capacity and complexity of spatial and temporal synaptic integration in Purkinje cells.
UR - http://www.scopus.com/inward/record.url?scp=0024535231&partnerID=8YFLogxK
U2 - 10.1113/jphysiol.1989.sp017490
DO - 10.1113/jphysiol.1989.sp017490
M3 - Journal article
C2 - 2585289
AN - SCOPUS:0024535231
VL - 409
SP - 157
EP - 170
JO - The Journal of Physiology
JF - The Journal of Physiology
SN - 0022-3751
IS - 1
ER -
ID: 237699495