Abstract
This study examined the effects of dopamine (DA), pressure ejected from multi-barrelled micropipettes, on the spontaneous and evoked activity of caudate neurons, recorded extracellularly in rats anesthetized with urethane. Neurons were categorized according to their discharge latencies in response to supramaximal cortical stimulation: neurons which fired with latencies <13 msec were classified "short-latency-discharge neurons", while neurons with latencies ≥ 13 msec were classified "long-latency-discharge neurons". This procedure also allowed the detection of neurons with low levels of spontaneous activity. The predominant effect of DA on both neuronal types was inhibition of spontaneous activity. However, DA exerted a modulatory effect in that spontaneous activity was inhibited at "doses" which did not affect activity evoked by cortical stimulation. Although DA-induced excitation was infrequent, it was significantly more prevalent among long-latency neurons than among short-latency-discharge neurons. Long-latency-discharge neurons were also significantly more spontaneously active than were short-latency neurons. In rats depleted of endogenous DA by treatment with reserpine, caudate neurons had significantly increased rates of spontaneous and evoked activity, shorter duration of stimulus-evoked inhibition, and longer latency for evoked discharges than in control rats. These results suggest that DA exerts modulatory effects on caudate neuronal activity. Furthermore, these results suggest that short- and long-latency-discharge neuronal groups may consist of pharmacologically, as well as physiologically, distinct neuronal types.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 843-851 |
| Number of pages | 9 |
| Journal | Neuropharmacology |
| Volume | 22 |
| Issue number | 7 |
| DOIs | |
| State | Published - 1983 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Cellular and Molecular Neuroscience
- Drug Discovery
- Pharmacology
Cite this
Effects of dopamine on spontaneous and evoked activity of caudate neurons. / Johnson, Steven; Palmer, M. R.; Freedman, R.
In: Neuropharmacology, Vol. 22, No. 7, 1983, p. 843-851.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of dopamine on spontaneous and evoked activity of caudate neurons
AU - Johnson, Steven
AU - Palmer, M. R.
AU - Freedman, R.
PY - 1983
Y1 - 1983
N2 - This study examined the effects of dopamine (DA), pressure ejected from multi-barrelled micropipettes, on the spontaneous and evoked activity of caudate neurons, recorded extracellularly in rats anesthetized with urethane. Neurons were categorized according to their discharge latencies in response to supramaximal cortical stimulation: neurons which fired with latencies <13 msec were classified "short-latency-discharge neurons", while neurons with latencies ≥ 13 msec were classified "long-latency-discharge neurons". This procedure also allowed the detection of neurons with low levels of spontaneous activity. The predominant effect of DA on both neuronal types was inhibition of spontaneous activity. However, DA exerted a modulatory effect in that spontaneous activity was inhibited at "doses" which did not affect activity evoked by cortical stimulation. Although DA-induced excitation was infrequent, it was significantly more prevalent among long-latency neurons than among short-latency-discharge neurons. Long-latency-discharge neurons were also significantly more spontaneously active than were short-latency neurons. In rats depleted of endogenous DA by treatment with reserpine, caudate neurons had significantly increased rates of spontaneous and evoked activity, shorter duration of stimulus-evoked inhibition, and longer latency for evoked discharges than in control rats. These results suggest that DA exerts modulatory effects on caudate neuronal activity. Furthermore, these results suggest that short- and long-latency-discharge neuronal groups may consist of pharmacologically, as well as physiologically, distinct neuronal types.
AB - This study examined the effects of dopamine (DA), pressure ejected from multi-barrelled micropipettes, on the spontaneous and evoked activity of caudate neurons, recorded extracellularly in rats anesthetized with urethane. Neurons were categorized according to their discharge latencies in response to supramaximal cortical stimulation: neurons which fired with latencies <13 msec were classified "short-latency-discharge neurons", while neurons with latencies ≥ 13 msec were classified "long-latency-discharge neurons". This procedure also allowed the detection of neurons with low levels of spontaneous activity. The predominant effect of DA on both neuronal types was inhibition of spontaneous activity. However, DA exerted a modulatory effect in that spontaneous activity was inhibited at "doses" which did not affect activity evoked by cortical stimulation. Although DA-induced excitation was infrequent, it was significantly more prevalent among long-latency neurons than among short-latency-discharge neurons. Long-latency-discharge neurons were also significantly more spontaneously active than were short-latency neurons. In rats depleted of endogenous DA by treatment with reserpine, caudate neurons had significantly increased rates of spontaneous and evoked activity, shorter duration of stimulus-evoked inhibition, and longer latency for evoked discharges than in control rats. These results suggest that DA exerts modulatory effects on caudate neuronal activity. Furthermore, these results suggest that short- and long-latency-discharge neuronal groups may consist of pharmacologically, as well as physiologically, distinct neuronal types.
UR - http://www.scopus.com/inward/record.url?scp=0020589409&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0020589409&partnerID=8YFLogxK
U2 - 10.1016/0028-3908(83)90130-2
DO - 10.1016/0028-3908(83)90130-2
M3 - Article
C2 - 6621814
AN - SCOPUS:0020589409
VL - 22
SP - 843
EP - 851
JO - Neuropharmacology
JF - Neuropharmacology
SN - 0028-3908
IS - 7
ER -