Histamine is a chemical substance released in inflammatory and allergic responses. The histamine H1 receptor is a G protein-coup
led receptor that activates phospholipase C in response to the binding of histamine. Complete the flowchart showing the process of histamine signal transduction from the H1 receptor. Place the items in the correct order:1. Calcium ions flow through the ligand-gated ion channel 2. Calcium ions activate a protein, leading to a cellular response 3. Calcium ion concentration increases in the cytosol. 4. IP 3 binds to a ligand-gated ion channel in the ER membrane 5. Enzyme cleaves PIP2, forming DAG and lP3