beta1- and beta2-adrenoceptor induced synaptic facilitation in rat basolateral amygdala.
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.
Abraham
Preetha Anna
PA
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.
Xing
Guoqiang
G
Zhang
Lei
L
Yu
Eric Z
EZ
Post
Robert
R
Gamble
Eleanore H
EH
Li
He
H
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
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D012333:RNA, Messenger; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D009638:Norepinephrine