in pineal sympathetic innervation are not significant in
the hyperproliferative effects of pinealectomy on the intestinal
crypts by Brian. D. Callaghan
Keywords: crypt cell proliferation, Wistar white rat,
superior cervical ganglion, pineal
July 31, 2000
Accepted: June 1, 2001
To observe the effect of changes in the pineal sympathetic
innervation on the crypt cell proliferation rate in the rat
small intestine, and compare these with the effect of pinealectomy
to determine the role of the sympathetic innervation in the
effect of pinealectomy.
METHODS: The effect of bilateral ablation of the superior
cervical ganglion, and that of pinealectomy on the crypt cell
proliferation rate in the rat small intestine was determined,
using a stathmokinetic technique.
RESULTS: Pinealectomy was associated with a considerably increased
crypt cell proliferation rate, whereas superior cervical ganglionectomy
was associated with a slightly decreased rate.
CONCLUSIONS: It appears likely that changes in pineal melatonin
production cannot be correlated directly with the effects
of pinealectomy on the crypts, although melatonin production
was not measured in this case. The role of loss of the non-adrenergic
innervation of the pineal in the effect of pinealectomy needs
to be examined. There is also other experimental evidence
that melatonin-free extracts of the pineal, containing as
yet unidentified substances, can influence mitotic activity
in some tissues, so the possible role of these substances
in the effects of pinealectomy should also be considered.
Furthermore, the superior cervical ganglion itself has an
extra-pineal role. Changes in pineal sympathetic innervation
are not significant in the hyperproliferative effects of pinealectomy
on the intestinal crypts.