BAM (Bovine Adrenal Medulla) Peptides

Definition
Bovine adrenal medulla (BAM) peptides are peptides secreted in the adrenal gland that exhibit potent opioid activity1.

Discovery
BAM peptides were first purified from bovine adrenal medulla and it was found that upon their trypsinization they can yield the other enkephalin peptide-Met Enkephalin2.

Classification
BAM peptides are cleavage products of the opioid peptide, pro-enkephalin. There are atleast three different BAM peptides that have been identified so far: BAM 12P, 20P and 22P3.

Structural Characteristics
BAM 22P is a docosa peptide that is a cleavage product of pro-enkephalin. BAM 20P and BAM 12P are C-terminal shortened versions of BAM 22P2.

Mode of action
BAM peptides normally bind to opioid receptors on neural cells and trigger a response. For instance, BAM22P binds to G-Protein coupled sensory neuro receptors and opioid receptors which when activated trigger a series of pain signals4.

Functions
BAM peptides mainly expressed in the central nervous system have potent opioid activity. BAM22P inhibits reflex bladder action, induces analgesic response in mice and also exerts a protective action during stress such as shock or injury4. The exact functions of other BAM peptides remain unclear.

References
1.Swain MG, MacArthur L, Vergalla J and Jones EA (1994). Adrenal secretion of BAM-22P, a potent opioid peptide, is enhanced in rats with acute cholestasis. Am J Physiol Gastrointest Liver Physiol , 266, G201-G205.
2.Mizuno K, Minamino N, Kangawa K and Matsuo H (1980). A new family of endogenous “big” met-enkephalins from bovine adrenal medulla: purification and structure of docosa- (BAM-22P) and eicosapeptide (BAM-20P) with very potent opiate activity. Biochem. and Biophy. Res. Comm., 47, 1283-90.
3.Book: Frank M and Klaus V, Molecular and Cellular Exercise Physiology.
4.Yanguo H, Peifang D, Jianping J and Xueai Z (2004). Dual effects of intrathecal BAM22 on nociceptive responses in acute and persistent pain–potential function of a novel receptor. Br J Pharmacol, 141(3): 423–430.