Mo. Lopezfigueroa et al., INNERVATION OF THE SHEEP PINEAL-GLAND BY NONSYMPATHETIC NERVE-FIBERS CONTAINING NADPH-DIAPHORASE ACTIVITY, The Journal of histochemistry and cytochemistry, 45(8), 1997, pp. 1121-1128
We used the NADPH-diaphorase histochemical method as a potential marke
r for nitric oxide synthase (NOS)-containing nerve fibers innervating
the pineal gland of the sheep. Nerve fibers containing NADPH-diaphoras
e activity provide dense innervation of the sheep pineal gland. The ne
rve fibers were located in the pineal capsule, in the connective tissu
e septae separating the lobuli of the gland, and penetrating between t
he pinealocytes. The nerve fibers were either smooth or endowed with b
outons en passant. After bilateral removal of the superior cervical ga
nglion, the dense network of NADPH-diaphorase-positive fibers was stil
l present in the gland. Ganglionectomy affected neither the distributi
on nor the appearance of the NADPH-diaphorase-positive fibers. Most of
the NADPH-diaphorase-positive fibers also contained peptide histidine
isoleucine and vasoactive intestinal polypeptide, and a comparatively
smaller fraction contained neuropeptide Y. Pinealocytes never exhibit
ed NADPH-diaphorase activity. These results demonstrate a major neural
input to the sheep pineal gland with NADPH-diaphorase-positive nerve
fibers of nonsympathetic origin.