Circumventing the blood-brain barrier with autonomic ganglion transplants.

Superior cervical ganglia, whose vessels are fenestrated and permeable to protein tracers such as horseradish peroxidase, were transplanted to undamaged surfaces in the fourth ventricle of rat pup brains. Horseradish peroxidase, infused systemically into the host, was exuded from the graft's vessels into the graft's extracellular stroma within 1 minute. At later times the glycoprotein reached the extracellular clefts of adjacent brain tissue, the vessels of which appeared to retain their impermeability. The blood-brain barrier to horseradish peroxide was thus bypassed where the extracellular compartments of graft and brain became confluent. The graft of autonomic ganglia can serve as a portal through which peptides, hormones, and immunoglobulins may likewise enter the brain.

Transplantation of central and peripheral monoamine neurons to the adult rat brain: techniques and conditions for survival.

The conditions for survival of transplants of peripheral and central monoamine neurons in the adult rat brain were studied using fluorescence histochemistry. Pieces of the superior cervical ganglion from newborn and adult rats and CNS tissue containing noradrenaline (NA), dopamine (DA) and indolamine (IA) neurons from embryonic, newborn and adult rats were transplanted to various brain sites using different techniques: insertion of the graft by means of a glass rod, by "injection", or by direct implantation of the graft in a resection cavity. Three principally different locations for the graft were tested: within the brain parenchyma in the caudal diencephalon and the caudate nucleus; onto the dorsal surface of the caudate nucleus; and onto the pial covering in the choroidal fissure after removal of the overlying cortex and parts of the hippocampal formation. Attempts were also made to transplant to the dorsal surface of the caudate nucleus or the hippocampus with the aid of an "artificial" vascular bed, achieved by previous transplantation of an iris. Consistent survival of the transplanted central and peripheral neurons was obtained only when the transplant was placed in contact with a vessel-rich tissue, such as the pia in the choroidal fissure or the "artificial" vascular bed. While the majority of the monoamine-containing neurons in the transplants died within the first month after transplantation, a significant number of neurons (up to about 150 in the ganglionic pieces and up to about 500 in the embryonic or newborn CNS pieces) survived for at least half a year in the brain. Survival of transplanted adult central monoamine neurons was not observed. A substantial outgrowth of axons was observed from all types of neurons in their new location. These newly formed fibers formed extensive fiber patterns within the transplant itself, around pia vessels, and within the adjacent brain tissue, above all in the hippocampal formation. The usefulness of the present transplantation technique for the exploration of mechanisms underlying reformation of axonal connections in the adult mammalian CNS is discussed.

Local blood flow and vascular permeability of autonomic ganglion-transplants in the brain.

The purpose of this study was to determine whether the blood vessels of transplanted neural tissue retain their functional characteristics. Quantitative autoradiography was used to measure local blood flow (F) with iodoantipyrine and the blood-to-tissue transfer constant (K) with alpha-aminoisobutyric acid in superior cervical ganglion (SCG) allografted to the surface of ventricle IV and into the cerebellum of the same rat. The F of the intraparenchymal grafts was slightly lower than that of the intraventricular grafts; F decreased between 1 and 4 weeks in SCG grafts at both sites. The permeability-surface area (PS) product of the microvessels and extraction fraction of AIB were calculated from these results and indicated restricted transvascular passage of the amino acid in both the in situ and grafted SCG. Surface area (S) and average length (L) of the microvessels were determined morphometrically and their permeability (P) was calculated from these data. Although K and PS decreased in the grafts compared to in situ SCG, a comparable decrease in S indicated that P was similar for the microvessels of both in situ and 1-week-old SCG transplants: 3.5-4.3 x 10(-6) cm/s. Between 1 and 4 weeks after transplantation, the P of the microvessels decreased to approximately 1.6-2.3 x 10(-6) cm/s without any change in S. Thus, the blood vessels of SCG grafts within or upon the brain initially retain the functional attributes of in situ SCG microvessels, but the average permeability of the graft microvessels decreases to approximately one half of the initial value by 4 weeks after transplantation.

[Effects on erectile function of transplanted major pelvic ganglion into the corpus cavernosum of adult rats with bilateral cavernous nerve injury].

OBJECTIVE: To investigate the effects on erectile function of transplanted major pelvic ganglion into the corpus cavernosum of adult male rats undergoing transection of bilateral cavernous nerves. METHODS: Twenty-six male Sprague-Dawley rats (3 - 4 month-old and 300 - 400 g/each) were divided into 2 groups: experimental group (transection of bilateral cavernous nerves and transplantation of left ganglion into left crus of penis, n = 16) and control group (transection of bilateral cavernous nerves only, n = 10). Erectile function was measured by injecting APO, and intracavernous pressure was measured 1 and 3 months afterwards by electric-stimulating the right major pelvic ganglion or the left crus. Half animals in each group were sacrificed 1 and 3 months afterwards for detecting nNOS-containing nerve fibers of corpus cavernosum. Electron microscopy of the implanted area was performed to assess neuronal survival. RESULTS: Both of the two groups have no erectile response to APO injection. Electrostimulation on the right major pelvic ganglion and left crus failed to produce erection in experimental group. The mean pressure changes in the two groups, measured by stimulating the left crus, were (9.41 +/- 3.20) and (4.16 +/- 2.58) cmH(2)O 1 month afterwards, and (13.67 +/- 4.18) and (5.09 +/- 2.74) cmH(2)O 3 months afterwards, respectively (P < 0.05). An increased number of nNOS-containing nerve fibers in left crus was detected in experimental group 1 and 3 months later, compared with control one (218.7 +/- 24.5, 18.0 +/- 3.7; 183.2 +/- 19.7, 19.0 +/- 3.8; P < 0.05). Ultrastructure examination by transmission electron microscope confirmed the survival of the implanted ganglion. CONCLUSION: Major pelvic ganglion can survive in the corpus cavernosum, and it has significant effects on the number of nNOS-containing nerve fibers and the alteration of intracavernous pressure.

[II. Ultrastructure of rat superior cervical ganglion cells in organ culture and grafts]. / II. Ultrastructure des cellules du ganglion cervical supérieur du rat en culture organotypique et en greffes directes.

Ultrastructural modifications of neurons in organ cultures were more and less obvious, while remaining always identical in cultures at the same age. Between 5 and 6 days after culture, neurons showed numerous dense bodies, nuclear pockets, sparse Nissl's bodies broken into fragments, bundles of microfilaments, elongated mitochondria and a slightly distended Golgi apparatus. Sometimes, the nucleus was indented and the nucleolus was shaded off. S.I.F. cells had indented nucleus, dense bodies and bundles of microfibrils. Neurons from direct grafts presented modifications similar to those observed in cultures at short time intervals. Then the breaking up of Nissl's bodies and mitochondria and the hyalin transformation of dense bodies took place. A restoration, at first involving the nucleus, could occur in relation with immunological conditions. The evolution of S.I.F. cells was quite comparable to that of neurons. In either case, features of cellular degeneracy were always little marked and fugitive.

[Survival of paraganglionic cells of the "SIF cells" type of the superior cervical ganglion of the rat]. / La survie des cellules paraganglionnaires du type "S.I.F. cells" du ganglion cervical supérieur de rat

A previous organotypic culture of rat's superior ganglion is propitious to the survey of grafts. Neurons keep their own structure for 15 to 18 months. A methodical study of grafts find rather rare or exceptionally frequent paraganglionary cells. These cells (S.I.F. Cells type) can keep their ultrastructural aspect in superior cervical ganglion graft for 15 months and even more.

[Cellular ultrastructure of the superior cervical ganglion of the rat in homo- and heterografts following organ culture of the transplant]. / Ultrastructure des cellules du ganglion cervical supérieur du rat, dans les homo et hétérogreffes, précédés de la culture organotypique du transplant.

Transplantation of the superior cervical ganglion of rat, after by organe culture retains ultrastructural integrity of the cells for a longer period than transplantation alone. Whatever the graft--homo or heterograft--neuronal survival is extended. Apart from minuts differences, S.I.F. cells show the same evolution. Ultrastructural features modified after culture always return to their initial state. Numerous after the culture always return to their initial state. Numerous after the culture, the lysosomes disappear in the first weeks following the graft. This cytoplasmic epuration is very important, since it might regenerate the cell and dilate its antigenic properties. Without the graft, the cytoplasmic epuration does not take place; vascularization is considered as a favourable factor of evolution. The association graft-culture has a double impact on survival of SCG cells. The culture initiates a cellular epuration, the graft quickens and perfects the return to a normal morphology.

[Reinnervation of internal organs and vessels by the neuropexy technic]. / Reinnervatsiia vnutrennikh organov i sosudov metodom neiropeksii.

Some new data on reinnervation of organs and vessels by means of transplantation of vegetative ganglia and sewing of neural branches are presented. When transplanting the cranial cervical ganglion to a muscle, and the caudal mesenteric ganglion to the urinary bladder wall, some neurocytes in the periphery of the ganglia are preserved; simultaneously, massive outgrowth of neural fibres occurs in the area of transplantation. These facts are considered as formation of a new local innervation center of the organ "recipient". The central part of the dog hypogastric nerve is sewed to the renal artery, in other experiments it is sewed into the rectum wall. A massive regeration of neural fibres along the course of the renal artery and the appearance of a neural ganglion in the rectum wall are stated. The sewed hypogastric nerve grows thicker, especially under the conditions of increased functioning of the organ "recipient". In a number of experiments, the large otic nerve is sewed to the common carotid artery. The development of a young connective tissue growing into the adventitia of the vessel is noted. Numerous regenerating neural fibres surrounding the vessel are noted in this tissue. Thus, a possibility of creating new or supplementary innervating connections of internal organs and vessels by means of sewing to them sensitive nerves or vegetative ganglia is morphologically substantiated.

Growth of locus coeruleus neurons in oculo independent of simultaneously present adrenergic and cholinergic nerves in the iris.

Fetal brain tissue pieces containing locus coeruleus (LC) neurons were grafted to the anterior eye chamber alone or together with other grafts (irides, sympathetic ganglia or additional LC) in the presence of the sympathetic and parasympathetic part of the autonomic ground plexus of the iris. Specimens were analyzed with quantitative fluorescence microscopy and uptake of [3H]metaraminol. LC neurons were shown to grow independently of the simultaneous presence of sympathetic fibers in oculo in the following three experimental situations: 1. Fetal LC grafted to normal eyes, analyzed after cessation of the production of the halo of fluorescent fibres on the host irides. 2. Maturated LC neurons in which growth is reinitiated by addition of an iris transplant which becomes completely innervated. 3. Fetal LC neurons placed on or opposite to iris transplants that in turn were introduced into the eye chamber 1 month before. All LC grafts produced halos of fluorescent fibres on both host irides and iris transplants in a restricted zone. Fetal LC grafts produced fluorescent nerve fibres on host irides independent of the removal of the parasympathetic fibres in the irides. Fetal LC grafts were not significantly inhibited in their fibre production on irides where maturated LC grafts had already formed a halo of densely packed fluorescent fibres. When two fetal LC grafts were introduced simultaneously into the same eye chamber both were able to produce fluorescent fibres together on the host iris. Sympathetic ganglion transplants formed normal looking adrenergic plexuses on host irides that were already carrying LC grafts with halos of fluorescent fibres. In conclusion, the fibre production of LC neurons in oculo is independent of the presence of sympathetic, and probably also parasympathetic, and maturated central NA nerves.