Choline acetyltransferase in bovine pineal gland.
Recent studies from our laboratories have shown that the bovine pineal gland contains a muscarinic cholinergic receptor with a Kd value of 0.423 +/- 0.010 nM and a Bmax value of 69.75 +/- 20.91 fmol/mg protein. In order to substantiate further the possible existence of a pineal cholinergic transmission, we have measured the activity of choline acetyltransferase and delineated its kinetic properties in the bovine pineal gland. This enzyme exhibited an activity of 0.0339 +/- 0.0042 nmol/mg protein/min. Furthermore, the bovine pineal choline acetyltransferase possessed a Km value of 124.86 +/- 24.06 microM and a Vmax value of 0.0598 +/- 0.0034 nmol/mg protein/min for acetyl CoA, and a Km value of 3.11 +/- 0.94 mM and a Vmax value of 0.0155 +/- 0.0016 nmol/mg protein/min for choline. The presence of muscarinic cholinergic receptors along with a specific choline acetyltransferase are supportive evidences that the bovine pineal gland may receive cholinergic innervation.
Phansuwan-Pujito
P
P
Laboratory of Neurobiology, Mahidol University, Salaya, Thailand.
Govitrapong
P
P
Ebadi
M
M
D000818:Animals; D002417:Cattle; D002421:Caudate Nucleus / Q000201:enzymology; D002531:Cerebellum / Q000201:enzymology; D002794:Choline / Q000494:pharmacology; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D002799:Cholinergic Fibers / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects; D006624:Hippocampus / Q000201:enzymology; D007700:Kinetics; D010296:Parietal Lobe / Q000201:enzymology; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism
D011950:Receptors, Cholinergic; D002795:Choline O-Acetyltransferase; D002794:Choline