TY - JOUR
T1 - Locus coeruleus stimulation potentiates local inhibitory processes in rat cerebellum
AU - Moises, Hylan C.
AU - Waterhouse, Barry D.
AU - Woodward, Donald J.
N1 - Funding Information:
out on 22 adult Sprague- 200 to 300 g. Animals were ‘This work was supported by NIDA grant DA-02238 to D.J.W. and an award from the Biologic~ Humanics Foundation. ‘Requests for reprints should be addressed to H. C. Moises at his current address: Department of Physiology, The University Medical School, Ann Arbor, MI 48109.
PY - 1983/6
Y1 - 1983/6
N2 - We previously reported that a low threshold action of norepinephrine (NE) on the cerebellar circuitry is expressed as an amplification of the inhibitory action of gamma aminobutyric acid (GABA) on Purkinje cell activity. Here we examined the effects of locus coeruleus (LC) stimulation on "off-beam" inhibitions of Purkinje cell firing induced by activation of local basket and stellate cell interneurons to determine whether endogenous NE, released from synaptic terminals, could induce a comparable enhancement of GABA-mediated synaptic input to these neurons. Stimulation of LC, at current intensities which by themselves were subthreshold for directly affecting background activity of Purkinje neurons, markedly increased off-beam inhibitory neuronal responses. Iontophoretic application of the beta-adrenergic blocker sotalol reversibly antagonized this enhancement of synaptic inhibition. In comparison, the potentiative effects observed with LC stimulation were increased by iontophoresis of the alpha-adrenergic blocker phentolamine. LC -induced increases in off-beam inhibition were not observed after destruction of cerebellar noradrenergic terminals by 6-hydroxydopamine. These results suggest that noradrenergic input from the LC can augment the efficacy of conventional GABA-mediated inputs synapsing on the Purkinje cell.
AB - We previously reported that a low threshold action of norepinephrine (NE) on the cerebellar circuitry is expressed as an amplification of the inhibitory action of gamma aminobutyric acid (GABA) on Purkinje cell activity. Here we examined the effects of locus coeruleus (LC) stimulation on "off-beam" inhibitions of Purkinje cell firing induced by activation of local basket and stellate cell interneurons to determine whether endogenous NE, released from synaptic terminals, could induce a comparable enhancement of GABA-mediated synaptic input to these neurons. Stimulation of LC, at current intensities which by themselves were subthreshold for directly affecting background activity of Purkinje neurons, markedly increased off-beam inhibitory neuronal responses. Iontophoretic application of the beta-adrenergic blocker sotalol reversibly antagonized this enhancement of synaptic inhibition. In comparison, the potentiative effects observed with LC stimulation were increased by iontophoresis of the alpha-adrenergic blocker phentolamine. LC -induced increases in off-beam inhibition were not observed after destruction of cerebellar noradrenergic terminals by 6-hydroxydopamine. These results suggest that noradrenergic input from the LC can augment the efficacy of conventional GABA-mediated inputs synapsing on the Purkinje cell.
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U2 - 10.1016/0361-9230(83)90211-3
DO - 10.1016/0361-9230(83)90211-3
M3 - Article
C2 - 6616270
AN - SCOPUS:0020960854
SN - 0361-9230
VL - 10
SP - 795
EP - 804
JO - Brain Research Bulletin
JF - Brain Research Bulletin
IS - 6
ER -