Thalamic arterial pattern: An endocast and scanning electron microscopic study in normotensive male rats

Abstract

Rat cerebral vasculature serves as a model for study of the pathophysiology of stroke in humans. Human thalamic arteries show a high incidence of stroke. The objective is to describe the thalamic arterial vascular pattern in normotensive male rats as the initial step for quantitative histochemical studies of enzyme activities in the walls of these vessels. Intracardiac injections of methyl methacrylate monomer provide detailed vascular endocasts. The thalamic vascular bed defined by in situ dissection, serial reconstruction, and light and scanning electron microscopy of endocasts contained four groups of vessel: ventral medial thalamic arteries, thalamic branches from the posterior cerebral artery, and ventral lateral and ventral anterior thalamic arteries. Thalamic vessels are muscular arterioles that, after three to four bipinnate branches, feed into a continuous capillary bed (no loops). The parent vessels and their subsequent branches have been evaluated in terms of their mean internal diameters, mean interbranch intervals, and branch angles. The arterial patterns to rat and human thalami are very similar, with the exception of the anterior choroidal artery which is missing in the rat. The branches supplying the thalamus in both the rat and human are closely associated with the circle of Willis; however, the constituent parts of the circle in rat vary from the pattern in human brain. The rat thalamic arteries show morphological features similar to those seen in the stroke-prone ganglionic arteries in the human basal ganglia.

In Vivo X-Ray Angiography in the Mouse Brain Using Synchrotron Radiation

“…The diameters of the cerebral arteries have been reported in rats, as measured by conventional histology or by the endocasting method using scanning electron microscopy. 3,16 Demonstration of cerebral vessels by endocasting method in mice has never been performed. Comparing between angiography and corrosion casting (or conventional histological study), we consider that the casting method contains many artifacts (eg, lack of pulsatile flow that is related to physiological shear stress on the endothelial cells, and tissue shrinkage and smooth muscle contraction attributable to fixation procedure).…”

Protective effects of the glutamate antagonist MK-801 on pyrithiamine- induced lesions and amino acid changes in rat brain

“…4B) is strikingly similar that the narrow lumen of the penetrating ventral medial branchto Figure 1 presented in the study of Papp et al (198 1) and es of the superior cerebellar artery make this region of thalamus suggests that 2 zones of vulnerability to PTD treatment exist highly susceptible to occlusive strokes and nonhemorrhagic inwithin thalamus and diencephalon. The reason for the early and farctions (Rieke, 1987). Swelling of brain parenchyma in the late stages of acute thiamine deficiency may lead to selective occlusion of these ventral medial arteriolar branches (Armstrong-James et al, 1988).…”

“…Alternatively, marked hypoperfusion (Hakim, 1986), possibly caused by edematous ischemia of the medial thalamus (Rieke, 1987), occurs during acute thiamine deficiency. Transient ischemia results in an increased release, decreased uptake (Drejer et al, 1985), and highly toxic extracellular levels of excitatory amino acids (Benveniste et al, 1984).…”

Microvascularization of thalamus and metathalamus in common tree shrew (Tupaia glis)

“…So far, studies of the thalamic and metathalamic vascular architecture with vascular corrosion cast technique in conjunction with scanning electron microscope (SEM) has been carried out only in the rat (Rieke 1987). It is of interest, therefore, to employ this method to same brain areas also in the common tree shrew (Tupaia glis), the animal regarded as a member of Order Scandentia with many features conforming to those of Order Primates (Mu¨ller et al 1999).…”