Final answer:
Chemicals, drugs, hormones, and neurotransmitters can indeed initiate smooth muscle contraction without an action potential through a process known as pharmaco-mechanic coupling, which is true.
Step-by-step explanation:
The statement that chemicals, drugs, hormones, and neurotransmitters can initiate a contraction without an action potential in smooth muscle is indeed true. This process is referred to as pharmaco-mechanic coupling and is different from the excitation-contraction coupling observed in skeletal muscles, where an action potential is necessary to trigger muscle contraction. In smooth muscle cells, various stimuli, such as the autonomic nervous system, hormones, or the presence of certain pharmaceutical agents, can directly cause muscle contraction by increasing intracellular calcium or through other mechanisms that bypass the necessity for an action potential. However, while this term describes the process accurately, it is more commonly referred to as pharmacomechanical coupling in the literature.