Browsing by Author "T.M. Jose"

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Hypothalainohypopliysial vascular and neurosecretory link in the teleost bagarius bagarius (Ham.)
(1975) A.G. Sathyajvesan; T.M. Jose
A three-dimensional picture of the hypothalamohypophysial neurosecretory system of B.bagarius could be obtained by adopting in situ staining techniques. The paired NPO give rise to left and right neurosecretory tracts which, although they approximate as a common tract, maintain their individuality till entering the pars intermedia. The ventral hypothalamic and the hypophysial arteries take their origin from I he internal carotid artery. The former contributes to the formation of the primary plexus of the median eminence and the latter enters the pituitary directly, giving rise to the ncuroadreno-interface vasculature. The vasculature of the median eminence lies in close contact with the long common neurosecretory tract. Morphological evidence suggests thal in li.bagarius there are three pathways of hypothalamic control of the hypophysis: (1) A direct neuroglandular pathway, where the neurosecretory axons come directly in contact with the adreno- hypophysial cells. (2) An indirect neurovasculoglandular pathway, where the blood exposed to the NSM at the median eminence comes in contact with gland cells. (3) Another indirect neurovasculoglandular pathway, where the blood is exposed to NSM at the neurohypophysis prior coming in contact with the gland cells. Thus, li.bagarius has the ‘median eminence equivalent’ neuroadeno-interface vasculature typical of the teleosts and the median eminence comparable to the pjlasmobranchs, Holocephali and primitive Actinopterygians. This shows that the pituitary portal system of teleosts is in general agreement with that of other lish groups, except that in some it is restricted to t he ncuroadreno-interface. whereas in ot hers like B. bagarius it extends to the hypothalamus also. These may be termed anterior and posterior median eminence. © 1975 S. Karger AG, Basel.
Hypothalamo-hypophysial neurosecretory and vascular system of the teleost Labeo rohita (Ham.)
(1977) T.M. Jose; A.G. Sathyanesan
The paired nucleus preopticus (NPO) lying on either side of the III ventricle gives rise to the left and right main neurosecretory tracts which proceed posteroventrally towards the pituitary and give rise to several finer axons which ramify the infundibular floor adjacent to the pituitary. Further, the main tracts unite into 1 or 2 common tracts and enter the pituitary. The bulk of the neurosecretory tracts enter the pars intermedia and few finer ones are seen among the pars distalis. The ventromedian component of the nucleus lateralis tuberis (NLT) is aldehyde fuchsin (AF) positive whereas the anterolateral neurons are AF negative. The internal carotid artery gives rise to the hypophysial and ventral hypothalamic arteries. The ventral hypothalamic artery gives rise to the primary capillary plexus at the infundibular floor region adjacent to the pituitary stalk. Portal vessels formed from this plexus largely irrigate the adenohypophysis. The hypophysial artery enters the neurohypophysis and gives rise to typical teleostean type neuroadenointerface vasculature. Morphological contact between the neurosecretory axons and primary capillary plexus at the floor of the infundibulum suggests the possibility of at least some active principles entering the blood vessels. Structurally L. rohita exhibited both tetrapodean and teleostean type of hypothalamo- hypophysial vasculature. Morphological evidences suggest a direct neuroglandular and an indirect neurovasculoglandular pathways of hypothalamic control of hypophysis in L. rohita.
Hypothalamohypophysial vascular and neurosecretory link in the teleost Bagarius bagarius (Ham.)
(1975) A.G. Sathyanesan; T.M. Jose
[No abstract available]
Pituitary cytology of the freshwater teleost Anabas testudineus (Bloch)
(1980) T.M. Jose; A.G. Sathyanesan
In the pituitary of A. testudineus the rostral pars distalis (RPD), proximal pars distalis (PPD) and pars intermedia (PI) are arranged in a rostro-caudal axis. The rostral neurohypophysis (NH) extends dorsal to the pars distalis, while the caudal part vertically penetrates into the PI and ramifies in its component. The RPD mainly consists of erythrosinophils and PbH-positive cells which are comparable to the lactotropes and corticotropes mentioned in the literature. In the nonbreeding season, acidophils are the predominant cells of the PPD and are largely confined to its dorsal aspect. The two types of cyanophils present in the PPD could not be differentiated with the various techniques used in this study. However, those cyanophils which increase in number and are active during the spawning season may be the gonadotropes, while those which are cytologically inactive may be the thyrotropes. The pars intermedia consists of PAS+ and PbH+ cells. Trichrome and tetrachrome staining techniques revealed the presence of acidophils, cyanophils and amphiphils in the PI.
Pituitary cytology of the Indian carp Labeo rohita (Ham.)
(1977) T.M. Jose; A.G. Sathyanesan
[No abstract available]
Structure of the neurohypophysis and the hypothalamo hypophysial vascularization in the teleost Channa punctatus Bloch
(1975) A.G. Sathyanesan; T.M. Jose
In C. punctatus the median eminence includes the subterminal region of the hypothalamus and the anterior neurohypophysis. It is formed of ependymal, fibrous and reticular layers as in the tetrapods. Primary capillary plexus extends from the subterminal region to the extremity of the anterior neurohypophysis. Only a few portal vessels from the hypothalamus enter in the pars distalis. All the components of pituitary including the pars intermedia are irrigated by the secondary plexus formed from the portal vessels emerging out of the anterior neurohypophysis. The neurosecretory axons and the ependymal cells are in close morphological contact with the primary plexus. Several axons have perivascular endings at the median eminence. Some axons were found to be only silver or aldehyde fuchsin positive whereas some others had taken up both. The silver positive axons were abundant in the pars distalis and the AF positive ones were more concentrated in the pars intermedia with greater accumulation of neurosecretory material.
Structure of the preoptico neurohypophysial complex of the teleost Nangra punctata (Day)
(1973) A.G. Sathyanesan; T.M. Jose
[No abstract available]