title: beta1- and beta2-adrenoceptor induced synaptic facilitation in rat basolateral amygdala.
abstract: The expression and characteristics of beta-adrenoceptor subtypes (beta1 and beta2) and their agonist actions on synaptic transmission in the basolateral amygdala (BLA) of the rat were examined using in situ hybridization, quantitative real-time PCR, Western blot analysis and field potential recording. In situ hybridization data revealed an intense distribution of beta1-and beta2-adrenoceptor mRNA in the BLA. Real-time PCR analysis of rat amygdala revealed significant transcriptional expression levels of both beta-adrenoceptors, with beta2-adrenoceptors outnumbering beta1-adrenoceptors in a ratio of 2.9 to 1. Bath application of the selective beta1-adrenoceptor agonist xamoterol hemifumarate (10 microM) facilitated the excitatory field synaptic potential evoked in the BLA by stimulation of the external capsule by 186.5+/-10.7% of control amplitude. In the presence of the selective beta1-adrenoceptor antagonist betaxolol hydrochloride (30 microM), the facilitating effects of field excitatory synaptic potential induced by the agonist were reduced to 126.1+/-2.3 % of control amplitude in the BLA. Bath application of the selective beta2-adrenoceptor agonist salmeterol (15 microM) facilitated the excitatory field synaptic potential evoked in the BLA by stimulation of the external capsule by 167.3+/-9.7 % of control amplitude. In the presence of the selective beta2-adrenoceptor antagonist ICI 118,551 HCl (30 microM), the facilitating effects of field excitatory synaptic potential induced by the agonist were reduced to 121.1+/-4.1 % of control amplitude in the BLA. These data suggest that beta-adrenoceptor mediated synaptic facilitation in the amygdala is mediated by both beta1 and beta2-adrenoceptor activation.
authors.affiliation: Center for the Study of Traumatic Stress, Department of Psychiatry, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA.
authors.forename: Preetha Anna
authors.initials: PA
authors.lastname: Abraham
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Xing
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Eric Z
authors.initials: EZ
authors.lastname: Yu
authors.forename: Robert
authors.initials: R
authors.lastname: Post
authors.forename: Eleanore H
authors.initials: EH
authors.lastname: Gamble
authors.forename: He
authors.initials: H
authors.lastname: Li
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000679:Amygdala / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D018342:Receptors, Adrenergic, beta-1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018343:Receptors, Adrenergic, beta-2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D012333:RNA, Messenger; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D009638:Norepinephrine