Changes in alpha 1-adrenergic neurotransmission alter the number of somatostatin receptors in the rat hippocampus.
The administration of an i.p. dose of phenylephrine (2 mg/kg) increased the number of [125I]Tyr11-somatostatin ([125I]Tyr11-SS) receptors and decreased their apparent affinity in rat hippocampal membranes 7 h after its injection. Prazosin (20 mg/kg, i.p.) administered 1 h before phenylephrine reversed effects of the latter on SS binding. Prazosin alone decreased the number of SS receptors without changing the affinity. The addition of phenylephrine or prazosin (10(-5) M) to the incubation medium did not change the SS binding characteristics. The present results support the notion that the alpha 1-adrenergic system regulates the binding of SS to its specific receptors in rat hippocampus.
López-Sañudo
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Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Alcalá, Madrid, Spain.
Arilla
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D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism; D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D006624:Hippocampus / Q000737:chemistry* / Q000502:physiology; D007858:Learning / Q000502:physiology; D010656:Phenylephrine / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D017481:Receptors, Somatostatin / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013004:Somatostatin / Q000031:analogs & derivatives / Q000378:metabolism / Q000502:physiology
D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D018340:Receptors, Adrenergic, alpha-1; D017481:Receptors, Somatostatin; D005576:Colforsin; D010656:Phenylephrine; D013004:Somatostatin; C032367:somatostatin, Tyr(11)-; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D015056:1-Methyl-3-isobutylxanthine; D011224:Prazosin