Hedlund P B, Finnman U B, Yanaihara N, Fuxe K
Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
Brain Res. 1994 Jan 14;634(1):163-7. doi: 10.1016/0006-8993(94)90271-2.
The aim of the present study was to evaluate whether galanin-(1-29) and galanin-(1-15) can modulate the 5-hydroxytryptamine1A (5-HT1A) receptors using [3H]8-OH-2-(di-n-propylamino)-tetralin ([3H]8-OH-DPAT) as a radioligand. Membrane preparations of the dorsal hippocampus, an area having the recently described [125I]galanin-(1-15) fragment binding sites, but having very few porcine [125I]galanin-(1-29) binding sites, were used. Galanin-(1-15) produced a concentration-dependent increase in the Kd value of [3H]8-OH-DPAT with a maximum effect of approximately 65% at 3 nM of galanin-(1-15), whereas galanin-(1-29) had no effect. This increase of the Kd value of [3H]8-OH-DPAT could be completely counteracted by the putative galanin antagonist M35 (1 nM). The Bmax values of [3H]8-OH-DPAT were not affected in any experiment. In conclusion, the present results give further evidence for the existence of a galanin receptor subtype mainly recognizing N-terminal galanin fragments, also having the ability to reduce the affinity of 5-HT1A receptors.
本研究的目的是使用[3H]8-羟基-2-（二正丙基氨基）四氢萘（[3H]8-OH-DPAT）作为放射性配体，评估甘丙肽-（1-29）和甘丙肽-（1-15）是否能调节5-羟色胺1A（5-HT1A）受体。使用了背侧海马体的膜制剂，该区域具有最近描述的[125I]甘丙肽-（1-15）片段结合位点，但猪[125I]甘丙肽-（1-29）结合位点极少。甘丙肽-（1-15）使[3H]8-OH-DPAT的Kd值呈浓度依赖性增加，在3 nM甘丙肽-（1-15）时最大效应约为65%，而甘丙肽-（1-29）无作用。[3H]8-OH-DPAT的Kd值增加可被假定的甘丙肽拮抗剂M35（1 nM）完全抵消。在任何实验中，[3H]8-OH-DPAT的Bmax值均未受影响。总之，本研究结果进一步证明存在一种主要识别N端甘丙肽片段的甘丙肽受体亚型，其也具有降低5-HT1A受体亲和力的能力。
