The Caudal Urophysis of Carasobarbus luteus and Capoeta trutta caught from river Tigris passing through Mosul city

Nabela M.S. Al-Shatter, ZohairI.F.Rahemo
Department of Biology, College of Science, University of Mosul,

Two freshwater fish models were selected, to study their caudal neurosecretory
system, caught in river Tigris passing through Neinava province. A total of 45
Carasobarbus luteus and 32 of , Capoeta trutta were examined to study their caudal
neurosecretory system of gross morphological and histological aspects. The caudal
spinal cord in B. luteus is a lobulted organ, possesses (3-5) lobules which are oval or
ovoid, each lobule measures (450-675) μm and average diameter is (270) μm, situated in
postero-ventral part of the spinal cord in the caudal region at the level of the last 5th
vertebrate, while spinal cord in C. trutta lacks these lobules. The caudal spinal cord
posseses three types of neurosecretory cells which appeared, after staining by three
different stains. These cells are situated at ventro- and ventro-lateral region of spinal
cord with respect to the central canal. These cells can be classified into three types,
small, median, and large cells.Noteworthy, Dahlgren cells are associated with blood
capillaries and it is easy to trace these cells with bulbous axons rich in secretary
materials as a large amount of neurosecretory material deposited in them. Furthermore,
neurosecretory material were deposited in the ventral part of the spinal cord which are
known as Herring bodies, and blood vessels were observed near them, some axons of
Dahlgren cells seen directed toward the blood capillaries

Keywords: fishes, urophysis, histology


[1] H. Chen, and R. Mu .Seasonal morphological and biochemical changes of Dahlgren
cells implies a potential of caudal neurosecretory system (CNSS) in the reproduction
cycle of teleostean fish. Fish Phys. Bioc., 34 (1),pp. 24-33, (2008)
[2] D.. Pearson, I.F. Shively, and R.R. Clark .Urotonsin II A somatostatin like peptide in
caudal neurosecretory system of fishes. Proc. Nat. Acad. Sci. U.S.A. 77 (8), pp. 5021-5024 ,( 1980).
[3]H. Bern. The elusive urophysis: Twenty-five years in pursuit of caudal
neurohormones. Amer. Zool., , 23 (3), pp. 763-769, ( 1985).
(4) K. Owada,M. Kawata, K. Akaji,A. Takag, M. Moriga, and H. Kobayashi .Urotensin II –
immunoreactive neurons in the caudal neurosecretary system of fresh water and
seawater fish. Cell and Tiss. Res., 239 (2), pp. 349-354, (1985)
(5) A. J. Ashworth, J.R. Banks, M.J. Brierley, and C.R. McCrohan. Electrical activity of
caudal neurosecretory neurons in sea water and fresh water – adapted Platichthys
flesusin vivo. J. Exp. Biol. 208,pp. 267-275, (2005)
(6) Z.I.F. Rahemo, and S.N. Ami.On the morphology of the urophysisspinalis and the caudal
neurosecretory system of the freshwater fish. Liza abu (Heckel).Basrah J. Agric. Sci.,
5 (1), pp. 89-100,( 1992).
(7) G. Fridberge and H.A. Bern. The Urophysis and the caudal neurosecretory system of
fishes. Biol. Rev., 43, pp. 175-199, (2008).
[8] M.J. Winter ,A. Ashworth, H. Bond, M. J. Brierley,andC.R. McCrohan. The caudal
neurosecretory system: Control and function of a novel neuroendocrine system in fish.
Bioc. Cell Biol., 78 (3), pp. 193-203, (2000).
[9] U. Holmgren. Neurosecretion in the teleost fish: The caudal neurosecretory system. Amer.
Zool., 4 (1), pp. 47-77, (1964).
[10] E. Gurr. Staining Animal Tissues: Practical and Theoretical. Loenard Hill., London ,(1962).
[11] L.G. Luna. Manual of Histological staining Methods of the armed forces institute of
pathology, 3 ed., McGraw – Hill Book Company, New York, (1968).

[12] C.F. Culling, R.T. Allison and W.T. Barr. Cellular pathology technique. Butterworth and
Co. (Publishers) Ltd. London, (1985).

[13] N. S. Gorgees, and Z.I.F. Rahemo, Z. I. F .Histomorphology of the caudal
neurosecretory system and urophysis of the freshwater teleost, Chondrostoma
regius (Heckel). Zool. Jb. Anat., 109,pp. 397-406, (1983).

[14] C. Parmentier, J. Taxl, R. Balment, G. Nicolas, and A. Calas. Caudal neurosecretory
system of zebra fish: ultrastural organization and immunocytochemical detection
of urotensins. Cell Tiss. Res. 235 (1), pp. 111-124,( 2006).
[15 ]C.R.McCrohan ,W. Lu, M.J. Brierley, L. Dow, and R.J. Balment (2007). Fish caudal
neurosecretory system: a model for the study on neuroendocrine secretion. Gen.
Comp. Endocrinol, 153 (1-3),pp. 243-25,(2007).
[16] G. Fridberg. Studies on the Caudal neurosecretory system. Int. J. Zool. 43 (1), pp. 3-7.
[17] C. Cioni, L. De Vito, A. Greco, and A. Pepe. The caudal neurosecretory system and its
afferent synapses in the gold fish, Carassius auratus: morphology,
immunohistochemistry, and fine structure. J. Morphol., 235 (1)pp. 59-76, (1998).