Blood supply of the rat hypothalamus. VI. Posterior region of the hypothalamus (nucleus hypothalamicus posterior, nuclei praemammillares, nucleus supramammilaris, mammilary body).

It was shown by the double ink-filling technique that the arteries of the rat premammillary region and mammillary body arise from the a. communicans posterior while these areas are drained by the anterior interpeduncular vein. Disregarding some minor overlaps and anastomoses, the blood supplies of the two territories are independent of each other and from the neighbouring areas of the hypothalamus, diencephalon and mesencephalon. Arteries of the premammillary region arise from the premammillary artery, except for some branches of the posterior tuberal and interpeduncular arteries. The mammillary body is supplied by three mammillary arteries (anterior, posterior and lateral). The premammillary region drains into the anterior and posterior premammillary veins. Venous blood of the mammillary body is collected by the anterior and posterior mammillary veins which end in the anterior interpeduncular vein. The circulation of individual premammillary and mammillary nuclei is described in detail.     

Blood supply of the rat hypothalamus. V. The medial hypothalamus (nucleus ventromedialis, nucleus dorsomedialis, nucleus perifornicalis)

Using the India ink double-perfusion technique, the blood vessels of the rat's medial hypothalamus were reconstructed from serial sections. The area studied comprised the ventromedial, dorsomedial and perifornical nuclei. The arterial supply of this territory comes from the middle hypothalamic and the anterior, middle and posterior tuberal arteries. The drainage is strictly undirectional: ventralward by the anterior, middle and posterior ventromedial, the posteromedial and posterolateral hypothalamic veins, all ending in the basal vein. The arteries of the ventromedial and dorsomedial nuclei are distinct from those of the arcuate nucleus and median eminence, and their drainage is not connected with the portal vessels. The nuclei studied, even at the levels of their subdivisions, possess own arteries whose territories of supply can well be distinguished with a minimum of overlap. The topography of these arteries is described in detail. The medial hypothalamus has no vascular connections with other regions of the diencephalon including the thalamus.     

Blood supply of the bed nucleus of the stria terminalis in rat

Summary The topographical distribution of the blood vessels in the bed nucleus of the stria terminalis (NIST) has been mapped in rats. Arteries and veins were visualized in red and blue by using a double-ink perfusion technique. Arteries supplying the NIST arise from the anterior cerebral artery directly or through the anterior communicating and interhemispheric arteries. Only a few, dorsal branches derive from the medial cerebral artery through thalamostriatal arteries. According to their terminal branches, NIST arteries can be divided into five groups: medial, ventral, lateral, septal and dorsal, which have only a relatively small overlap in their territories. About 90% of veins from the NIST drain into the major basal veins. Medial branches run into the perioptic and interhemispheric veins, while the ventral branches and the large lateral vein drain directly into the anterior cerebral vein. A small proportion of NIST veins run dorsalward into the vena cerebri magna via thalamostriatal veins.     

Blood supply of the rat amygdala.

The cerebral vessels of the rat were filled with inks of different colours. The topography of the vessels of the amygdala were reconstructed from serial sections. The circulation of the individual amygdaloid nuclei was studied in detail. The arteries of the amygdala arise from the deep and cortical branches of the internal carotid and middle cerebral arteries. Eight major arteries were found to supply blood to the amygdala. All amygdaloid nuclei receive branches from both arterial trunks. The vast majority of the veins are collected by the middle cerebral and basal veins. Only a small fraction drains into the hippocampal vein. Of particular importance are the veins ending in the basal vein and those cortical ones that run in the rhinal sulcus. All amygdaloid nuclei have a multidirectional drainage.     

Innervation of somatostatin synthesizing neurons by adrenergic, phenylethanolamine-N-methyltransferase (PNMT)-immunoreactive axons in the anterior periventricular nucleus of the rat hypothalamus

The adrenergic innervation of somatostatin synthesizing neurons located in the anterior region of the rat hypothalamic periventricular nucleus was studied by means of a light and electron microscopic immunocytochemical double labelling technique. This region which is the source of hypophysiotrophic somatostatin immunoreactive (IR) neurons also receives a dense plexus of adrenergic axons as determined by immunocytochemistry of phenylethanolamine-N-methyltransferase (PNMT), the marker enzyme for the central adrenergic system. The simultaneous detection of PNMT and somatostatin antigens in hypothalamic sections of colchicine pretreated animals revealed a congruency in the distribution of the labelled elements and also close juxtaposition of PNMT-IR axons to somatostatin producing neurons. At the ultrastructural level, axo-somatic and axo-dendritic synaptic connections were found between PNMT-containing axons and somatostatin expressing neurons. These morphological findings support the view that the central adrenergic system might influence the production and secretion of growth hormone in the pituitary gland by a direct monosynaptic interaction with somatostatin synthesizing neurons.     

Innervation of somatostatin synthesizing neurons by adrenergic,phenylethanolamine-N-methyltransferase (PNMT)-immunoreactive axons in the anterior periventricular nucleus of the rat hypothalamus

Summary The adrenergic innervation of somatostatin synthesizing neurons located in the anterior region of the rat hypothalamic periventricular nucleus was studied by means of a light and electron microscopic immunocytochemical double labelling technique. This region which is the source of hypophysiotrophic somatostatin immunoreactive (IR) neurons also receives a dense plexus of adrenergic axons as determined by immunocytochemistry of phenylethanolamine-N-methyltransferase (PNMT), the marker enzyme for the central adrenergic system. The simultaneous detection of PNMT and somatostatin antigens in hypothalamic sections of colchicine pretreated animals revealed a congruency in the distribution of the labelled elements and also close juxtaposition of PNMT-IR axons to somatostatin producing neurons. At the ultrastructural level, axo-somatic and axo-dendritic synaptic connections were found between PNMT-containing axons and somatostatin expressing neurons. These morphological findings support the view that the central adrenergic system might influence the production and secretion of growth hormone in the pituitary gland by a direct monosynaptic interaction with somatostatin synthesizing neurons.     

Estrogen regulation of proteins in the rat ventromedial nucleus of the hypothalamus

The effects of estradiol (E2) on the expression of proteins in the pars lateralis of the ventromedial nucleus of the hypothalamus (VMNpl) in ovariectomized rats was studied using 2-dimensional gel electrophoresis followed by RPLC-nanoESI-MS/MS. E2 treatment resulted in the up-regulation of 29 identified proteins. Many of these proteins are implicated in the promotion of neuronal plasticity and signaling.     

Proteomic analysis of the ventromedial nucleus of the hypothalamus (pars lateralis) in the female rat

The use of proteomics to study changes in the expression of CNS proteins, which may underlie the regulation of physiological and/or behavioral responses, represents an emerging application of this technology. In the current study, the Palkovits' microdissection method was evaluated as a means of obtaining proteomic data from discrete brain nuclei. The pars lateralis of the ventromedial nucleus of the hypothalamus (VMN) was chosen for the initial studies because of its established role in the expression of gonadal hormone dependent female sexual behavior. The VMN from ovariectomized rats was microdissected from 300 microm frozen brain sections using a 500 microm punch. Total proteins were separated using 2-DE. A group consensus of 432 protein spots, visualized by SYPRO Ruby stain, was obtained from gels from four independent VMN samples. A low mean CV and high gel-to-gel correlation coefficients indicate that reproducible 2-DE gels can be generated from microdissected tissue samples. Proteins from the mediobasal hypothalamus (MBH) were also separated on 2-DE gels. Evaluation of the 2-DE maps from the VMN and the MBH revealed different protein profiles, and indicates that microdissection improves the detection of low-abundance proteins, and reduces the relative occurrence of abundant proteins on 2-DE maps.     

Arterial supply of the anterior ear.

Twenty cadaver auricles were injected with a latex solution to define the arterial supply of the anteroauricular surface. Two arterial networks exist, the network of the triangular fossa-scapha and the network of the concha. Both eventually communicate on the anthelix. The triangular fossa-scapha network originates from one subbranch of the upper auricular branch of the superficial temporal artery and from branches of the posterior auricular artery that come through the earlobe and triangular fossa and over the helical margin. The conchal network is provided by two to four perforators that come from the posterior auricular artery, piercing the conchal floor. Auricular branches of the superficial temporal artery in the preauricular region and their communications with the posterior auricular artery also were confirmed. We believe that a greater understanding of the detailed arterial anatomy in this area allows one to develop safely a variety of surgical techniques for reconstruction of the ear.     

Blood supply of the trachea and bronchi in the rat

Existence of longitudinal and circular arterio-arterial anastomoses are stated, as well as various ways of outflow from the veins of the organs studied; this demonstrates essential compensatory abilities of this bed in blood supply regulation and draining at inflow and outflow from the microcirculatory system bed. Different topography of the arterial sources, venous plexuses, capillary fields allows to suppose different histophysiology of the tracheal zones mentioned: the anterior (laryngotracheal), middle and posterior (bifurcational). For the tracheal microcirculatory bed, metamerically repeated microcirculatory areas are peculiar. Distribution of the bronchial arteries takes place up to the terminal bronchi. In the area of the latter, anastomoses of the bronchial vessels with the pulmonary artery are observed.     

Sex difference in volume of the ventromedial nucleus of the hypothalamus in the rat

The volume of the ventromedial nucleus of the hypothalamus (VMN) of normal male rats was significantly greater than that of normal female rats. Castration of day 1 neonatal males significantly reduced the volume of the VMN to a level comparable with that of normal females. However, the VMN volume was no longer influenced by castration on day 7. Injection of 1.25 mg testosterone propionate to 5- to 15-day-old females did not have any significant effect on the volume of the VMN. These results indicate that the volume of the VMN is sexually dimorphic and is modified by internal secretion of neonatal testes.