Which of the following elements is not typically involved in chemical signaling?

Gap junctions are structures that allow direct communication between adjacent cells through the exchange of ions and small molecules, facilitating electrical signaling in tissues. They form channels between the cytoplasm of two cells, enabling rapid transmission of signals without the need for chemical mediators. Unlike hormones, enzymes, and neurotransmitters, which are involved in specific signaling pathways—regulating various physiological processes by binding to receptors or catalyzing reactions—gap junctions operate through a direct physical connection, making them not typical participants in chemical signaling.

Therefore, while hormones, enzymes, and neurotransmitters play key roles in communicating signals across longer distances or between different cell types through chemical means, gap junctions provide a distinct mode of intercellular communication that does not involve chemical signaling in the classical sense.