Sympathetic post-ganglionic transmission

Question

BlackTom AI · Accepted Answer

Question restatement: The topic is sympathetic post-ganglionic transmission, and we must evaluate which description correctly characterizes the signalling pathways involved for adrenergic receptors.
Option a: 'Acts only through the PLC-beta signalling pathway' would imply that all sympathetic post-ganglionic transmission uses PLC-beta exclusively. This is misleading because beta adrenergic receptors typically couple to Gs proteins that stimulate adenylate cyclase and increase cAMP, not PLC-beta, so this option ignores the well-established cAMP pathway for beta receptors.
Option b: 'Acts only through the Adenylate cyclase / cAMP signalling pathway' would ignore the fact that alpha-adrenergic receptors commonly couple to Gq proteins that activate PLC-beta and generate inositol trisphosphate (IP3) and diacylglycerol (DAG). Since alpha receptors can signal through PLC-beta, a statement asserting exclusivity to cAMP would be incomplete.
Option c: 'Involves beta adrenergic receptors acting through the Adenylate cyclase / cAMP signalling pathway and alpha adrenergic receptors acting through or the PLC-beta pathway' presents a mixed model: beta receptors signaling via AC/cAMP and alpha receptors signaling via PLC-beta (the Gq pathway). This aligns with the canonical dichotomy where beta receptors predominantly use the cAMP route, while alpha-1 receptors often engage PLC-beta signaling. The wording also allows for the alpha pathway to be active via PLC-beta, which is consistent with known alpha-1 signaling.
Option d: 'Involves alpha adrenergic receptors acting through the Adenylate cyclase / cAMP signalling pathway and beta adrenergic receptors acting through or the PLC-beta pathway' flips the typical coupling: alpha receptors are not predominantly linked to AC/cAMP signaling; they are primarily associated with PLC-beta via Gq. Similarly, beta receptors are not primarily coupled to PLC-beta. Hence this option misattributes the main pathways to each receptor type.
Option e: 'Involves alpha or beta adrenergic receptors that act either through the Adenylate cyclase / cAMP signalling pathway or the PLC-beta pathway' suggests that either receptor type can independently choose between pathways in all cases. In physiology, while there is diversity, the typical associations are more specific (beta with cAMP, alpha with PLC-beta). This option is overly vague and does not reflect the common, receptor-specific coupling patterns, making it an inaccurate generalization.
Overall, option c accurately reflects the complementary signalling roles of beta receptors via adenylate cyclase / cAMP and alpha receptors via PLC-beta, while the other choices correspond to oversimplifications or misattributions of receptor–pathway couplings.

Sympathetic post-ganglionic transmission单项选择题

类似问题

Question at position 62 True or False: Stimulation of alpha-1 receptors on the heart will result in an increased heart rate.TrueFalse

Stimulation of beta-1 receptors on cardiac muscle cells will result in:

True or false: Stimulation of alpha receptors will cause vasoconstriction in arterioles.

The alpha and beta receptors belong to which division of the ANS?

Sympathetic nervous system postganglionic fibres synapse on:

Delivering adrenaline via an 'Epi Pen' during anaphylactic shock has which of the following benefits?

Adrenaline acts on:

What was the world's first widely adopted biodiversity policy?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单