After one frog's heart has been stimulated, an extract of fluid from that heart can make a second frog's heart beat faster. What conclusion did Otto Loewi draw from these results?
A) Transmission at synapses is a chemical event.
B) The sympathetic and parasympathetic nervous systems are antagonistic.
C) Transmission at heart muscle synapses is electrical.
D) Hormones facilitate the actions of the nervous system.

Question

Quizplus · Accepted Answer

Otto Loewi's experiment demonstrated that transmission at synapses is a chemical event, as the extract of fluid from one frog's stimulated heart was able to affect the heartbeat of another frog's heart. This led to the discovery of the neurotransmitter acetylcholine.

After One Frog's Heart Has Been Stimulated, an Extract of Fluid