In vivo voltammetric monitoring of norepinephrine release in the rat ventral bed nucleus of the stria terminalis and anteroventral thalamic nucleus.
The role and contribution of the dense noradrenergic innervation in the ventral bed nucleus of the stria terminalis (vBNST) and anteroventral thalamic nucleus (AV) to biological function and animal behaviors is poorly understood due to the small size of these nuclei. The aim of this study was to compare norepinephrine release and uptake in the vBNST with that in the AV of anesthetized rats. Measurements were made in vivo with fast-scan cyclic voltammetry following electrical stimulation of noradrenergic projection pathways, either the dorsal noradrenergic bundle (DNB) or the ventral noradrenergic bundle (VNB). The substance detected was identified as norepinephrine based upon voltammetric, anatomical, neurochemical and pharmacological evidence. Fast-scan cyclic voltammetry enables the selective monitoring of local norepinephrine overflow in the vBNST evoked by the stimulation of either the DNB or the VNB while norepinephrine in the AV was only evoked by DNB stimulation. The alpha2-adrenoceptor antagonist yohimbine and the norepinephrine uptake inhibitor desipramine increased norepinephrine overflow and slowed its disappearance in both regions. However, control of extracellular norepinephrine by both autoreceptors and uptake was greater in the AV. The greater control exerted by autoreceptors and uptake in the AV resulted in reduced extracellular concentration compared with the v BNST when large numbers of stimulation pulses were employed. The differences in noradrenergic transmission observed in the terminal fields of the v BNST and the AV may differentially regulate activity in these two regions that both contain high densities of norepinephrine terminals.
Department of Chemistry and Neuroscience Center, University of North Carolina , Chapel Hill, NC 27599-3290, USA.
Jinwoo
J
Park
Brian M
BM
Kile
R Mark
RM
Wightman
D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D020643:Anterior Thalamic Nuclei / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003891:Desipramine / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism; D018492:Dopamine Antagonists / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods*; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008839:Microelectrodes; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012686:Septal Nuclei / Q000378:metabolism*; D014018:Tissue Distribution / Q000187:drug effects; D015016:Yohimbine / Q000494:pharmacology
D018759:Adrenergic Uptake Inhibitors; D000317:Adrenergic alpha-Antagonists; D000779:Anesthetics, Local; D018492:Dopamine Antagonists; D018765:Dopamine Uptake Inhibitors; D010879:Piperazines; D015016:Yohimbine; D020891:Raclopride; C043425:vanoxerine; D008012:Lidocaine; D003891:Desipramine; D004298:Dopamine; D009638:Norepinephrine