Projections of the amygdala and septum to the caudate nucleus of the cat brain

By means of the retrograde axonal transport of horseradish peroxidase in the cat, direct projections of neurons in the magno- and mediocellular parts of the basal nucleus of the amygdalar complex have been stated nearly to all parts of the caudate nucleus and projections of a small amount of neurons in the nucleus of the Brocka diagonal ligament--only to the medial edge of the caudate nucleus. The possibility to divide the caudate nucleus into limbic and non-limbic parts is discussed.     

Ultrastructural changes in the septum pellucidum of the cat brain after its long-term self-stimulation

During prolonged electrical stimulation of the septum (self-stimulation 2-3 h daily for 2.5 months) perikarion of most neurons, situated around the tip of the stimulating electrode undergoes peripheral chromatolysis, less part of the neurons is shrunk, mitochondria are desorganized, invaginations of the nuclear membrane occur more often and deeper. Intercellular clefts are sharply dilated, profiles of altered myelin fibers are observed, presynaptic terminals decrease in their number. Axonal terminals with agglutinated vesicles become more numerous. In other terminals osmiophilic bodies and membranous inclusions are revealed. Under electric stimulation a sharp reaction of glial cells, especially astrocytes is observed. One group of astrocytes participate in phagocytosis of the degenerating structures, while the other--in formation of the glial scar.     

Retino-pulvinar pathway of the cat brain

Peculiarities on axonal distribution and termination of the retinal ganglionar cells within the limits of the thalamic pulvinar nuclei have been studied in 10 cats by means of the radioautography method combined with silver nitrate impregnation (Fink--Heimer technique). The ganglionar cells have projections on two pulvinar nuclei -- the lateral and the inferior. The medial pulvinar nucleus has no similar connections. The retinal projections in the pulvinar nuclear complex are bilateral and nearly symmetrical, the contralateral projections of the pathway somewhat predominate.     

Effect of electrocoagulation of the septum on the behavior and memory of the cat

Lesion effects of various areas of the septum on general behaviour, learning and memory were studied in cats. It appeared that electrocoagulation of the medial septum alone leading to the disappearance of the hippocampal theta rhythm does not result in the development of the septal syndrome signs; does not disturb the normal structure of the sleep-wakefulness cycle; does not delay the elaboration of instrumental alimentary reflexes (to approach two feeders) or their extinction, but does entirely disturb the delayed responses to conditioned stimuli. In cases when lesion involves also the lateral septum, it produces the development of all signs of the septal syndrome (hyperemotionality, hyperactivity, rage, hyperphagia, etc.), disturbance of the normal structure of the sleep-wakefulness cycle, delay of both the elaboration and extinction of instrumental alimentary reflexes, disturbance of pre-elaborated conditioned reactions with sound discrimination, entire disturbance of conditioned delayed responses. On the basis of these data, the specific significance of hippocampal theta-rhythm in the organization of learning and memory is rejected, and a more important role is attributed to the descending regulatory influence exerted by the hippocampus and other archipaleocortical structures on the activating and motivatiogenic structures of mesodiencephalon.     

Caudate-cortical connections in the cat brain

By means of optical and electron microscopic methods, the cortical fields from the ipsilateral hemisphere was analysed in the cat after electrocoagulation of the dorsal part in the nucleus caudatus (NC). Degenerating axonal preterminals and terminals were detected in the preparations impregnated after Nauta--Gygax and Wiitanen's methods and in electronograms. To exclude degeneration of cortical and projective thalamic fibrillae from the great number of regenerated conductors, additional operations were performed on the same cats--thalamic and ventral NC nuclei were damaged and coagulative electrode was inserted into the dorsal NC a month before the last operation.     

Ultrastructure of arterioles in the cat brain

Summary A total of 110 arterioles were examined in the brains of cats; different sites were studied including the cortex, putamen, pons and crus cerebri. No internal elastic laminae were seen in the subendothelial space, although occasional fragments of elastic material were present in the larger arterioles. The media was composed of one, two or three layers of smooth muscle cells which interlocked in such a way that the vessel wall thickness was constant. Numerous tight junctions were seen between adjacent smooth muscle cells and between the endothelium and smooth muscle cells. Apart from the usual cell organelles, the smooth muscle cells of arterioles had numerous dense patches on the cell surface. The structure of the adventitia varied according to the diameter of the vessel and the site in the brain; it contained adventitial cells, bundles of collagen fibres and nerve fibres. Innervation of arterioles was more constant in the brain stem than in the cortex. Metarterioles had less specialised, atypical smooth muscle cells, a discontinuous media and numerous, extensive myoendothelial tight junctions; they were not innervated by nerve fibres. The diameter of metarterioles was less than 10 m whereas that of arterioles was 10–45 m. The possible functional aspects of arteriolar innervation are discussed.     

Ultrastructure of venules in the cat brain

Summary Intracerebral venules of the cat were examined to establish criteria for a distinct separation between the venous and arterial system, and to characterize, in greater detail, the mural construction of individual venules. The intracerebral venules were compared with those of other organs. Venules do not have a vascular wall composed clearly of endothelium, media, and adventitia, as is characteristic of arteries and arterioles. The venous endothelium has a similar structure to that of capillaries. The periendothelial cells of the venule differ in shape depending on the vascular diameter. The number of periendothelial cell processes in postcapillary venules increases progressively. Segments in which the basal lamina of the endothelium merges with that of the glia cover a smaller portion of the circumference than in venous capillary loops. In collecting venules, the endothelium is almost completely enveloped by periendothelial cells which have a larger number of filaments. There are no typical smooth muscle cells in the intracerebral venules. The perivascular space becomes wider in collecting venules, contains adventitial cells, phagocytes and a great number of collagen fibers.     

Alpha-neo-endorphin-like immunoreactivity in the cat brain stem

This paper examines the distribution of fibers and cell bodies containing alpha-neo-endorphin in the cat brain stem by using an indirect immunoperoxidase technique. A high or moderate density of immunoreactive cell bodies was found in the superior central nucleus, nucleus incertus, dorsal tegmental nucleus, nucleus of the trapezoid body, and in the laminar spinal trigeminal nucleus, whereas a low density of such perikarya was observed in the inferior colliculus, nucleus praepositus hypoglossi, dorsal nucleus of the raphe, nucleus of the brachium of the inferior colliculus, and in the nucleus of the solitary tract. The highest density of immunoreactive fibers was found in the substantia nigra, dorsal motor nucleus of the vagus, nucleus coeruleus, lateral tegmental field, marginal nucleus of the brachium conjunctivum, and in the inferior and medial vestibular nuclei. These results indicate that alpha-neo-endorphin is widely distributed in the cat brain stem and suggest that the peptide could play an important role in several physiological functions, e.g., those involved in respiratory, cardiovascular, auditory, and motor mechanisms.     

Immunocytochemical localization of enkephalin in the lateral septum of the guinea-pig brain

By the use of antisera to met-enkephalin and leu-enkephalin, enkephalin-containing structures were visualized in the lateral septum of the guinea-pig brain. The present results do not reveal immunoreactive perikarya in this area. The immunostaining is exclusively located in numerous nerve fibers and endings mostly encompassing neuronal perikarya, which accounts for the fact that at the light-microscopic level cellular somata appear to be immunostained. The immunoreactive terminals and fibers contain granules approximately 110 nm in diameter and synaptic vesicles. The origin and the functional role of these numerous enkephalin terminals remain to be established.     

Neuronal porosome in the rat and cat brain

It is well established that during cell secretion, membrane-bound secretory vesicles dock and fuse at the base of supramolecular cup-shaped structures at the cell plasma membrane called "porosomes", to expel intra-vesicular contents to the outside. In neurons, it has been demonstrated that 12-17 nm cup-shaped lipoprotein structure possessing a central plug are present at the presynaptic membrane, where 50 nm in diameter synaptic vesicles transiently dock and fuse to release neurotransmitter. In the past decade, the neuronal porosome has been isolated and its major chemical composition determined. Additionally, the porosome has been both structurally and functionally reconstituted into artificial lipid membrane, establishing its role as the secretory portal in neurons. Studies utilizing atomic force and electron microscopy, combined with electron density and 3D contour mapping, provide at the nanoscale, the structure and assembly of proteins within the neuronal porosome. In the current study, ultrahigh resolution imaging of the presynaptic membrane of isolated brains from both rats and cats, demonstrate for the first time, the presence of neuronal porosomes in cat brain, and further confirms the presence of porosomes at the presynaptic membrane in rat brain synaptosomes. Results from the present study further confirm the cup-shaped morphology of porosomes in the rat brain, and demonstrates their similar shape and size in the cat nerve terminal. The study also demonstrates for the first time, the universal presence of similar porosomes in different species of mammals.     

Neuronal porosome in the rat and cat brain

It is well established that during cell secretion, membrane-bound secretory vesicles dock and fuse at the base of supramolecular cup-shaped structures at the cell plasma membrane called “porosomes”, to expel intra-vesicular contents to the outside. In neurons, it has been demonstrated that 12–17 nm cupshaped lipoprotein structure possessing a central plug are present at the presynaptic membrane, where 50 nm in diameter synaptic vesicles transiently dock and fuse to release neurotransmitters. In the past decade, the neuronal porosome has been isolated and its major chemical composition determined. Additionally, the porosome has been both structurally and functionally reconstituted into artificial lipid membrane, establishing its role as the secretory portal in neurons. Studies utilizing atomic force and electron microscopy, combined with electron density and 3D contour mapping, provide at the nanoscale, the structure and assembly of proteins within the neuronal porosome. In the current study, ultrahigh resolution imaging of the presynaptic membrane of isolated brains from both rats and cats, demonstrate for the first time, the presence of neuronal porosomes in cat brain, and further confirms the presence of porosomes at the presynaptic membrane in rat brain synaptosomes. Results from the present study further confirm the cup-shaped morphology of porosomes in the rat brain, and demonstrates their similar shape and size in the cat nerve terminal. The study also demonstrates for the first time, the universal presence of similar porosomes in different species of mammals.     

Interaction of reticular structures in the brain of the cat

In acute and chronic experiments on 35 cats an inhibitory influence was found of the caudal reticular nucleus of pons Varolii on unit activity of the sensorimotor cortex and dorsal part of the midbrain reticular formation. The influence of this structure on unit activity of the ventral part of the midbrain reticular formation was mainly of a facilitatory character. Activation of the ventral part inhibited the unit activity of the dorsal part of the same structure. Consequently, the caudal reticular nucleus of pons Varolii elicits inhibition at the level not only of the cerebral cortex but also of the midbrain reticular formation (of its dorsal part). The character of these influences coincides with that of unit activity changes of these two areas of the midbrain reticular formation during the development of the paradoxical phase of sleep. The obtained facts must underlie the stopping of convulsive activity in this phase of sleep.     

Transformations of prostaglandin H2 in the cat brain

1. Active mouse bone collagenase is excluded from its inhibitory antibody by preincubation of that antibody with various forms of inactive enzyme, e.g. 'procollagenase', some collagenase-inhibitor complexes or partially denatured or degraded collagenase. This property allows the detection of several enzymatically inactive forms of collagenase. 2. The accumulation of immunoreactive collagenase in the culture fluid of mouse bones occurred only in the presence of heparin and was not correlated with bone resorption induced by parathyroid hormone. These experiments provide further (see Lenaers-Claeys, G. and Vaes, G., Biochim. Biophys. Acta (1979) 584, 375-388), more conclusive evidence that the critical role in the resorption of the organic matrix of these explants may be due to another enzyme system than collagenase.     

Neuronal organization of the periamygdaloid cortex in the cat brain

Neuronal organization of the fields Pmm, Pml2, Pe and epm of the periamygdaloid cortex of the cat brain has been studied by means of Golgi and Nissl methods. The field Pmm essentially differs from other fields of this cortex by primitiveness of its cytoarchitectonic an neuronal organization (two layers uniform by the composition of their neurons are distinguished, the structure of the latter is relatively primitive). In the medial part of this field long axonal rarely branching short dendritic, and in the lateral part--poorly differentiating pyramidal and spindle-like cells predominate. The field Pmm can be considered as a transitional formation between the subcortex (the medial nucleus of the amygdaloid body) and other fields of the periamygdaloid cortex. The fields Pml2, Pe and epm are built more complexly: the cells are organized in 4 layers, more complexly differentiated by their form and size than in the field Pmm and correspondingly more various (long axonal densely branching cells are observed: pyramidal and spindle-like--of the cortical type and bushy--of the subcortical type, as well as long axonal rarely branching reticular cells). The short axonal cells in the fields Pml2, Pe and epm are rather variable in their form, size and direction of axons; in the field Pmm they are less numerous. The field Pmm and the complex of the fields Pml2, Pe and epm are perhaps different in their function, this is evident from different projection of their neurons. Axons of the cells in the field Pmm get into less differentiated and the most ancient medial nucleus of the amygdaloid body and into the ancient system of connections of the latter--terminal strip, and neurons of the fields Pml2, Pe and epm are projected into the basolateral part of the amygdaloid body and into the external capsule--phylogenetically younger structures. Besides, poverty of the axonal collateralies in the long axonal neurons and a small amount and uniformity of the forms of the short axonal cells in the field Pmm and contrary, rich collateralies and variety of short axonal cells in the composition of other fields demonstrate more complex internal integrative function, performing in that composition.     

Microwave-induced thermoelastic pressure wave propagation in the cat brain

This paper presents direct measurements of acoustic pressure wave propagation in cat brains irradiated with pulsed 2.45-GHz microwaves. Short rectangular microwave pulses (2 microseconds, 15 kW peak power) were applied singly through a direct-contact applicator located at the occipital pole of a cat's head. Acoustic pressure waves were detected by using a small hydrophone transducer, which was inserted stereotaxically into the brain of an anesthetized animal through a matrix of holes drilled on the skull. The measurements clearly indicate that pulsed microwaves induce acoustic pressure waves which propagate with an acoustic wave velocity of 1523 m/s.