Cross-modulation of synaptic plasticity by beta-adrenergic and 5-HT1A receptors in the rat basolateral amygdala.
Neurotransmitter receptors are often colocalized in a neuron with other receptors, and activation of one receptor can either amplify or antagonize the response to a colocalized receptor. The aim of this study was to investigate the cross-regulation of synaptic transmission by beta-adrenergic and serotonin 1A (5-HT1A) receptors and to elucidate their underlying mechanisms. Stimulation of presynaptic beta-adrenergic receptors with isoproterenol (Iso) in the basolateral amygdala resulted in a long-lasting increase in synaptic transmission. This effect was mimicked by forskolin, an activator for adenylyl cyclase and a cAMP analog. In addition, the effect of forskolin was blocked by catalytic and regulatory site antagonists for cAMP-dependent protein kinase (PKA), indicating a PKA-mediated mechanism. Application of 5-HT depressed the synaptic transmission and blocked Iso- and forskolin-induced potentiation. The effect of 5-HT was mimicked by the selective 5-HT1A agonist 8-hydroxy-dipropylaminotetralin and was blocked by the selective 5-HT1A antagonist 1-(2-methoxyphenyl)-4[4-(2-phthalimido)butyl]piperazine, indicating its mediation by 5-HT1A receptors. To determine the locus of interaction, Sp-cAMPS, a membrane-permeable activator of PKA, was applied, and the potentiation produced by Sp-cAMPS was completely blocked in slices pretreated with 5-HT. These results suggest that the interaction between the intracellular signaling pathways activated by 5-HT1A and beta-adrenergic receptors occurs at a step downstream from cAMP production.
Wang
S J
SJ
Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan City, Taiwan 701.
Cheng
L L
LL
Gean
P W
PW
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D019204:GTP-Binding Proteins / Q000502:physiology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020239:Receptor Cross-Talk / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D011985:Receptors, Serotonin / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1; D013569:Synapses / Q000502:physiology*
D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D005576:Colforsin; D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins; D007545:Isoproterenol