Noradrenaline induces short and long duration potentiation of glutamate excitations of cultured Purkinje neurons.
The effects of iontophoretic application of noradrenaline on spontaneous or glutamate-evoked activity were studied in Purkinje neurons in explant cultures. The most frequently observed effect of noradrenaline was a depression of glutamate responses, and this was sometimes observed in the absence of apparent changes in spontaneous activity. In 30 out of 80 cells, glutamate responses were increased during or following noradrenaline application. In 21 of the 30 cells, these potentiations were of relatively short duration (less than 4 min), while in the other 9, the potentiations had a much longer duration. beta-Adrenergic antagonists blocked the long duration potentiations in four out of five cells, while short duration potentiation was blocked in only one of eight cells. The alpha-adrenergic antagonist prazosin blocked the short duration potentiations in six of eight cells. The results indicate that long duration potentiations by noradrenaline as reported in the hippocampus are also observable in the cerebellum, and that short and long duration potentials of glutamate responses may be pharmacologically distinct.
Marshall
K C
KC
Department of Physiology, Faculty of Health Sciences, University of Ottawa, Ont., Canada.
Tsai
W H
WH
D000818:Animals; D002478:Cells, Cultured; D004357:Drug Synergism; D005971:Glutamates / Q000494:pharmacology*; D051379:Mice; D009638:Norepinephrine / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011689:Purkinje Cells / Q000187:drug effects / Q000502:physiology*; D011941:Receptors, Adrenergic / Q000187:drug effects; D013997:Time Factors
D005971:Glutamates; D011941:Receptors, Adrenergic; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin