Which of the following act through G protein coupled receptors

Which of the following act through G
protein coupled receptors?
a) Ach Muscarinic receptors
b) Insulin receptors
c) Ach Nicotinic receptors
d) GABA-A receptors
Correct Answer - A
Ans: A. Ach Muscarinic receptors
Ref: Lippincott, 6’t’ed., Pg. 27-28
Ml, M2, M3, M4 and M5 are Ach Muscarinic receptors.
They are G protein coupled receptors