Physiology · Digestive system

Gastric acid secretion: converging signals in the parietal cell

Two signals can regulate the same function without being equivalent. This map brings acetylcholine/M3 and histamine/H2 together around gastric acid secretion, linking that function to the parietal cell, an ion transport mechanism class and luminal acidity. Their convergence helps separate the contribution of each explanatory level.

KatavMD team · Neora Systems S.EP
Editorial update: 11 November 2026

Explore this map in the Atlas

Opens acid secretion with receptors, mechanism, histology and anatomy.

The map

Acetylcholine and M3 receptor, and histamine and H2 receptor, converge on gastric acid secretion and the parietal cell, linked to ion pump, gastric body and luminal acidity. — Atlas view prepared with 10 nodes and 12 relationships. M3 and H2 share a function and effector cell; the gastric body provides the regional context.

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What each connection means

Read the ligand–receptor pairs first, then their arrows toward secretion. “Site of action” places both receptors in the parietal application. “Effector participant” connects that cell to the function. Anatomy locates the system; it does not add a signaling step between receptor and secretion.

Endogenous agonist: Identifies a substance capable of activating the subtype. Acetylcholine does not act exclusively at M3, nor does histamine act exclusively at H2.
Modulates · increases: Indicates a stimulatory influence with preserved activation and coupling. Each edge expresses an effect; it does not calculate the net response to all signals.
Uses mechanism and occurs in: Ion pump supplies a mechanism class; gastric body supplies a representative location. Neither relationship alone is equivalent to the complete function.

Signals and their shared function

Two receptor inputs

Acetylcholine/M3 and histamine/H2 reach the same secretory function and parietal context. Convergence indicates a shared functional target without implying equal potency, identical intracellular mechanisms or a linear sum of responses. The M3 application retains its partial-support designation.

Histamine release

Gastric histamine release is a process; histamine is the chemical entity that activates H2. The map connects release to acid secretion through a stimulatory influence. Notes describe a paracrine signal from ECL cells, although those cells are not displayed as a node in this selection.

Effector and location

The parietal cell represents the oxyntic phenotype in fundic/body glands. Its gastric body application does not assign acid secretion to the entire epithelium or exclude other territories. Histological context defines where receptor and function links should be interpreted.

From transport mechanism to luminal outcome

The “Ion pump” node is a general cellular function class. Its relationship note mentions primary H/K transport as a contribution to secretion, but this view does not include a specific molecular pump. Receptor and pump have different roles: one receives a regulatory signal, while the transport mechanism contributes to ion movement.

Acid secretion and increasing luminal acidity are also different concepts. Their relationship holds buffering capacity and gastric emptying constant. If those conditions change, the same secretion can accompany a different acidity. Greater acidity means lower pH; the “increases” arrow refers to acidity rather than to a numerical increase in pH.

What each source demonstrates

The human study by Pfeiffer and colleagues characterizes M3 receptors through radioligand binding in gastric mucosa. That design supports the subtype in the tissue, but does not independently identify every receptor-bearing cell or measure secretion by an isolated parietal cell. The parietal application therefore combines sources and retains its partial-support classification.

Tanaka-Shintani and Watanabe examine immunostaining and cellular distribution in resected stomachs. Their work provides context for the ECL population; detecting markers is not equivalent to demonstrating histamine release. IUPHAR catalogs clarify receptor identities and ligands, while physiological texts contextualize the integrated function. These are complementary contributions with different evidential scopes.

Convergence means a shared function, not a calculated net response

Two stimulatory arrows are insufficient to calculate acid output. The notes require viable cells and functional machinery, while acknowledging other concurrent signals. The map organizes selected influences; it does not include an integration equation.

Explore for yourself

Follow each ligand to its receptor and compare where M3 and H2 converge. Open the notes for both modulatory relationships.
Inspect the parietal cell and its gastric body application. Distinguish site of action, effector participant and anatomical location.
Follow secretion toward luminal acidity and read the buffering and emptying conditions. Compare the human tissue, histological and regulatory references. Some notes remain in their original Spanish.

Explore this map in the Atlas

Opens acid secretion with receptors, mechanism, histology and anatomy.

Scope and sources

The selection does not represent every gastric regulator, inhibitor or feedback circuit. It cannot establish a clinical response, a secretion magnitude or a treatment effect. It preserves distinctions between a function, a luminal variable, a mechanism class and a cellular context.

Sources recorded in the notes and checked for this guide. Human studies contribute specific evidence; the review is listed as contextual synthesis rather than an additional experiment: