Autoradiographic studies of central alpha 2A- and alpha 2C-adrenoceptors in the rat using [3H]MK912 and subtype-selective drugs.
In the present study we examined the distribution of alpha 2A- and alpha 2C-adrenoceptors in tissue slices from the rat cervical spinal cord and from brain slices collected at the level of the striatum. To differentiate between alpha 2A- and alpha 2C-adrenoceptors, the slices were incubated with [3H]MK912 in the presence of graded concentrations of the alpha 2A-selective drug, BRL44408, or the alpha 2C-selective drug, spiroxatrine. Computer analysis of the autoradiograms indicated that 0.4 nM [3H]MK912 plus 185 nM BRL44408 selectively labeled alpha 2C-adrenoceptors, while 0.4 nM [3H]MK912 plus 220 nM spiroxatrine selectively labeled alpha 2A-adrenoceptors. Using this approach, alpha 2C-adrenoceptors were detected in the striatum, while alpha 2A-adrenoceptors predominated in the cortical layers 1-4, the spinal cord distal dorsal horn, the septum and the endopiriform nucleus.
Uhlén
S
S
Department of Pharmaceutical Biosciences, Uppsala University, Sweden. staffan.uhlen@bmc.uu.se
Lindblom
J
J
Johnson
A
A
Wikberg
J E
JE
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive / Q000502:physiology; D003342:Corpus Striatum / Q000737:chemistry; D004146:Dioxanes / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D054833:Isoindoles; D008297:Male; D011807:Quinolizines / Q000378:metabolism / Q000494:pharmacology*; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D018341:Receptors, Adrenergic, alpha-2 / Q000032:analysis* / Q000378:metabolism; D012686:Septal Nuclei / Q000737:chemistry; D013003:Somatosensory Cortex / Q000737:chemistry; D013116:Spinal Cord / Q000737:chemistry; D013141:Spiro Compounds / Q000494:pharmacology; D014316:Tritium
C547770:Adra2a protein, rat; C547776:Adra2c protein, rat; D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D018492:Dopamine Antagonists; D007093:Imidazoles; D007211:Indoles; D054833:Isoindoles; D011807:Quinolizines; D018341:Receptors, Adrenergic, alpha-2; D013141:Spiro Compounds; D014316:Tritium; C054290:L 657743; C018387:spiroxatrine; C072125:BRL 44408