Neuropeptide
PACAP
PACAP encompasses distinct peptide forms, including PACAP-38 and PACAP-27. In vitro studies have compared them through adenylyl cyclase responses and other signaling pathways.
This is a research reference, not a product offered in the Asciende catalog. Published studies do not establish the identity, purity or availability of a commercial preparation.
Local signaling and experimental context
Record where and how the measurement was made. Presence of a peptide in a system does not establish that a commercial preparation reproduces that system.
- Does the work study an isolated molecule, endogenous secretion or a preparation containing several components?
- Are tissue, species and response measurement specified?
- Does the interpretation distinguish signal detection from demonstration of its function in that model?
Mechanism described in the literature
In cellular systems with experimentally expressed receptors, PACAP responses depend on the ligand form and receptor variant. A cyclic AMP readout does not necessarily describe the phospholipase C response.
Other names in the literature
- Pituitary adenylate cyclase-activating polypeptide
The assay behind the name
The 1989 work isolated a peptide from sheep hypothalamic tissue by tracking activity in rat pituitary cells. The preparation showed adenylyl cyclase activity and different secretory readouts. Its name preserves that experimental history without establishing its only physiological function (PMID 2803320).
PACAP-27 is more than an abbreviation
In 1990, a shorter form was identified during purification, and its synthetic replica was compared with PACAP-38. Both shared activity in the adenylyl cyclase assay used. That agreement belongs to a specific readout and does not make the entities identical (PMID 2383262).
The expressed receptor also matters
A 1993 publication examined alternatively processed receptor variants. In vitro, ligand-variant combinations produced different patterns for adenylyl cyclase and phospholipase C. Laboratories can therefore study PACAP yet obtain different profiles if their systems express different receptors (PMID 8396727).
Questions and answers
Is writing PACAP enough to describe an experiment?
Specify PACAP-27 or PACAP-38 when the publication identifies the form.
Does a similar cyclic AMP response imply identical signaling?
No. The receptor-variant study compared pathways that did not respond equivalently.
Sources
- Isolation of a novel 38 residue-hypothalamic polypeptide which stimulates adenylate cyclase in pituitary cells. — Biochem Biophys Res Commun, 1989
- Isolation of a novel 38 residue-hypothalamic polypeptide which stimulates adenylate cyclase in pituitary cells.
- Isolation of a neuropeptide corresponding to the N-terminal 27 residues of the pituitary adenylate cyclase activating polypeptide with 38 residues (PACAP38). — Biochem Biophys Res Commun, 1990
- Isolation of a neuropeptide corresponding to the N-terminal 27 residues of the pituitary adenylate cyclase activating polypeptide with 38 residues (PACAP38).
- Differential signal transduction by five splice variants of the PACAP receptor. — Nature, 1993
- Differential signal transduction by five splice variants of the PACAP receptor.