Non-vasopressinergic, non-oxytocinergic neuropeptides in the rat hypothalamo-neurohypophyseal tract: experimental immunohistochemical studies.
The hypothalamo-neurohypophyseal tract is known to contain the classical neurohypophyseal hormones vasopressin and oxytocin. Additionally, dynorphin, methionine- and leucine-enkephalin, cholecystokinin (CCK), corticotropin-releasing factor (CRF), and galanin are co-stored with vasopressin and/or oxytocin. Recent immunohistochemical studies have revealed the existence of a low to moderate number of substance P-, vasoactive intestinal peptide (VIP)-, neuropeptide Y (NPY)- and somatostatin-immunoreactive nerve fibers within the rat neurohypophysis. VIP-, substance P- and NPY-immunoreactive fibers were distributed throughout the organ, whereas somatostatin-immunoreactive fibers were present in the proximal part of the organ. The positive nerve endings were either large in size resembling classical nerve terminals related to perivascular spaces, or smaller similar to peptidergic fibers as described in the CNS. These results indicate that these neuropeptides may be either co-stored with the classical neurohypophyseal hormones or contained in another system of afferents to the organ. The probably distinct functional roles of these neuropeptides in the physiology of the neurohypophysis are discussed.
Mikkelsen
J D
JD
Institute of Medical Anatomy B, University of Copenhagen, Denmark.
Schmidt
P
P
Sheikh
S P
SP
Larsen
P J
PJ
D000818:Animals; D007030:Hypothalamo-Hypophyseal System / Q000166:cytology*; D007150:Immunohistochemistry; D009478:Neuropeptide Y / Q000032:analysis; D009479:Neuropeptides / Q000032:analysis*; D010121:Oxytocin / Q000032:analysis; D051381:Rats; D013373:Substance P / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis; D014667:Vasopressins / Q000032:analysis
D009478:Neuropeptide Y; D009479:Neuropeptides; D014667:Vasopressins; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D010121:Oxytocin