Which form of intercellular communication allows small molecules or ions to pass directly between the cytoplasms of adjacent animal cells?

Core Concept

Gap junction channels connect the cytoplasms of adjacent animal cells and permit ions and small signaling molecules to pass directly between them. Plants use plasmodesmata for a related form of direct cytoplasmic communication. Endocrine, paracrine, and synaptic signaling instead release signals into extracellular space.