Answer:
GTP-bound form
Step-by-step explanation:
Such a receptor may be associated with the GDP-regulated G-stimulant protein system. When the neurotransmitter binds to the receptor, the protein G-GDP complex is activated by separating its β subunit. When the ligand "sticks" to it, it releases GDP and allows GTP to bind. This form of the G protein that binds GTP, is the activated ("on") form of it. When it is "on" it releases signals into the cell. After a short period (seconds or less) the G protein hydrolyzes the GTP to GDP and itself "turns off".