PROCTOLIN - PEPTIDE TRANSMITTER CANDIDATE IN INSECTS
PROCTOLIN - PEPTIDE TRANSMITTER CANDIDATE IN INSECTS
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DOI：
10.1016/0024-3205(75)90133-2
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发表时间：
1975-01-01
期刊：
影响因子：
6.1
通讯作者：
BROWN, BE
中科院分区：
文献类型：
--
作者：
BROWN, BE
参考神经刺激、谷氨酸、5-HT 和 proctolin（最近从大蠊中分离和鉴定的一种肌力肽）引起的反应，对美洲大蠊 (L.) 的前肠 (后肠) 缓慢的横纹肌进行了药理学检查。 5-HT 和 proctolin 分别在阈值浓度约为 10−7 和 10−9 M 时模拟重复神经刺激引起的分级收缩；对谷氨酸（∼ 10−4 M）的反应没有类似的分级。 5-HT 受体与其他受体（包括突触后受体）不同，因为它们被溴麦角酸二乙酰胺特异性阻断。 Proctolin 在 TTX 处理或手术去神经的肌肉上完全活跃，表明 Proctolin 受体位于肌纤维膜上。阈值水平为 5× 10− 8 M 的酪胺可逆地拮抗由直肠素和神经刺激引起的反应，但对 5-HT 和谷氨酸反应没有影响。阈下浓度的 proctolin 会增强神经诱发反应，但谷氨酸则不会。从药理学角度来看，前泌乳素和突触后受体似乎与谷氨酸和 5-HT 受体相同且不同。由于已知直肠素是直肠神经传出通路的组成部分，因此证据表明它可能充当兴奋性递质物质。肽能传递的讨论与直肠神经末梢的超微结构组织有关，其中除了电子透明的突触小泡之外，还含有神经节段颗粒。
The slow, striated muscles of the proctodeum (hindgut) of the cockroach, Periplaneta americana (L.), were examined pharmacologically with reference to the responses evoked by nerve stimulation, glutamate, 5-HT, and proctolin, a myotropic peptide from Periplaneta recently isolated and identified. The graded contractions evoked by repetitive nerve stimulation were simulated by 5-HT and proctolin at threshold concentrations of about 10− 7 and 10− 9 M respectively; responses to glutamate (∼ 10− 4 M) were not similarly graded. The 5-HT receptors are distinct from other receptors, including the post-synaptic receptors, since they were specifically blocked by bromolysergic acid diethylamide. Proctolin was fully active on TTX-treated or surgically denervated muscle indicating that the proctolin receptors are located on the muscle fibre membrane. Tyramine, at threshold levels 5× 10− 8 M, reversibly antagonized the responses evoked by proctolin and by nerve stimulation but was without effect on the 5-HT and glutamate responses. Neurally evoked responses were potentiated by subthreshold concentrations of proctolin but not by glutamate. Pharmacologically, the proctolin and post-synaptic receptors appear to be identical and distinct from the glutamate and 5-HT receptors. Since proctolin is known to be a constituent of an efferent pathway of the proctodeal nerves, the evidence suggests that it may function as an excitatory transmitter substance. Peptidergic transmission is discussed in relation to the ultrastructural organization of the proctodeal nerve terminals which contain neurosectory granules in addition to electron-lucent, synaptic vesicles.