title: Noradrenergic enhancement of Ca2+ responses of basal dendrites in layer 5 pyramidal neurons of the prefrontal cortex.
abstract: Although the excitatory effects of noradrenaline have been thoroughly studied in the central nervous system, there is relatively little known about the adrenergic effects on Ca2+ dynamics of dendrites. In the present study, we imaged basal dendrites of layer 5 pyramidal neurons in the prefrontal cortex using two-photon microscopy. In our experiments noradrenaline, applied in the bath, enhanced excitability of layer 5 pyramidal neurons. The number of evoked action potentials following current injection to the soma increased by 44.7% on average. In the basal dendrites and spines the evoked Ca2+ responses were also markedly enhanced. Noradrenaline-induced effects could be blocked by the beta-adrenergic blocker propranolol. Our data, that activation of the noradrenergic system increases excitability of layer 5 pyramidal neurons via beta-adrenergic receptors and enhances Ca2+ signaling in basal dendrites, suggest a cellular site of action for noradrenaline to improve the integrative capabilities of dendrites.
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Szigony u. 43, Hungary.
authors.forename: Albert M I
authors.initials: AM
authors.lastname: Barth
authors.forename: E Sylvester
authors.initials: ES
authors.lastname: Vizi
authors.forename: Balazs
authors.initials: B
authors.lastname: Lendvai
mesh_terms: D015502:Absorptiometry, Photon; D000200:Action Potentials / Q000187:drug effects; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism*; D004594:Electrophysiology; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000502:physiology
chemical_list: D000316:Adrenergic alpha-Agonists; D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D002118:Calcium; D009638:Norepinephrine