Ong J, Kerr D I, Johnston A R
Neurosci Lett. 1987 Jun 1;77(1):109-12. doi: 10.1016/0304-3940(87)90616-1.
In the guinea-pig isolated ileum, both gamma-aminobutyric acid (GABA) and baclofen induced a dose-dependent depression of cholinergic twitch contractions to transmural stimulation, sensitive to delta-aminovaleric acid (DAVA) and phosphonobaclofen (phaclofen). beta-Phenyl-GABA (BPG) antagonised this depressant action of baclofen and GABA, whilst itself weakly depressing ileal twitch contractions, an effect insensitive to DAVA or phaclofen, and thus unrelated to any GABAB-receptor-mediated effects. These results suggest that the baclofen receptors in the ileum that are antagonised by BPG differ from either of baclofen receptors in the spinal cord, where the presynaptic receptors are blocked by phaclofen and the postsynaptic receptors are insensitive to phaclofen, with BPG having baclofen-like actions at both sites. Interaction of BPG and baclofen with different receptor populations may explain the differing therapeutic actions of these compounds.
在豚鼠离体回肠中，γ-氨基丁酸（GABA）和巴氯芬均可剂量依赖性地抑制经壁刺激引起的胆碱能抽搐收缩，这种抑制作用对δ-氨基戊酸（DAVA）和磷酰巴氯芬（phaclofen）敏感。β-苯基-GABA（BPG）可拮抗巴氯芬和GABA的这种抑制作用，而其自身对回肠抽搐收缩仅有微弱的抑制作用，该作用对DAVA或phaclofen不敏感，因此与任何GABAB受体介导的效应无关。这些结果表明，被BPG拮抗的回肠中巴氯芬受体与脊髓中的两种巴氯芬受体均不同，在脊髓中，突触前受体被phaclofen阻断，突触后受体对phaclofen不敏感，而BPG在这两个部位均具有类似巴氯芬的作用。BPG与巴氯芬与不同受体群体的相互作用可能解释了这些化合物不同的治疗作用。
