What type of response is elicited by G-protein linked receptors compared to channel-linked receptors?

• A. Fast and short-lived
• B. Slow and long-lasting
• C. Immediate and irreversible
• D. Fast and enduring

Answer: (B)

G-protein linked receptors, also known as metabotropic receptors, initiate a signaling cascade that often involves secondary messengers, leading to downstream effects that can modify cellular activity over a longer period. This process typically results in a slow and long-lasting response because the activation of G-proteins can either amplify the signal through several steps or lead to multiple pathways that affect various cellular functions.

In contrast, channel-linked receptors open ion channels in response to binding a ligand, which produces a quick and direct change in the membrane potential. This leads to rapid and transitory physiological responses, as the effects are immediate and cease soon after the channel closes.

Thus, G-protein linked receptors are characterized by their ability to create prolonged physiological effects distinct from the fast-acting responses associated with channel-linked receptors. This fundamental difference in the mechanism of action underlines why the response elicited by G-protein linked receptors is accurately described as slow and long-lasting.