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At least 55 records · Page 3Linked to original sources

Parasympathetic innervation of cephalic arteries in rabbits: comparison with sympathetic and sensory innervation.

We investigated the distribution of parasympathetic, sympathetic, and sensory perivascular nerve fibers in rabbit cephalic arteries supplying the brain, exocrine glands, nasal mucosa, masseter muscles, tongue, and skin in the face and also examined cranial autonomic and sensory ganglia. NADPH diaphorase (NADPHd)-positive and vasoactive intestinal peptide-like immunoreactive (VIP-LI) neurons were located in the cranial parasympathetic ganglia. Neuropeptide Y (NPY)-LI neurons occurred mainly, and dopamine beta-hydroxylase (DBH)-LI neurons occurred exclusively, in the superior cervical (sympathetic) ganglion. Substance P (SP)-LI and calcitonin gene-related peptide (CGRP)-LI neurons occurred only in the trigeminal (sensory) ganglion. Therefore, it was assumed that NADPHd-positive and VIP-LI perivascular nerve fibers in cephalic arteries were parasympathetic, all DBH-LI and most NPY-LI fibers were sympathetic, and SP-LI and CGRP-LI fibers were sensory in nature. In the cerebral arteries, NADPHd-positive and VIP-LI varicose fibers were more numerous in the rostral than in the caudal half of the Circle of Willis. In the extracranial arteries, NADPHd-positive and VIP-LI fibers were most abundant in the lingual, lacrimal, and supraorbital arteries; sparse in the parotid and submandibular arteries; and absent in the ear artery. There was an obvious proximal-to-distal density gradient along individual cephalic arterial trees. In contrast, DBH-LI, NPY-LI, SP-LI, and CGRP-LI varicose nerve fibers were similar in density in all cephalic arteries and their branches. These neuroanatomical findings suggest that differential parasympathetic innervation in cephalic arteries may play a role in the partitioning of blood flow between different cephalic tissues.

Animals↗

Motoneurons innervating the cremaster muscle of the rat are characteristically densely innervated by serotoninergic fibers as revealed by combined immunohistochemistry and retrograde fluorescence DAPI-labelling.

The lumbar spinal cord of the rat was studied by combined retrograde fluorescent labelling with 4',6-diamidino-2-phenylindole-2HCl (DAPI) and immunoperoxidase procedure using serotonin antiserum. A peculiar small neuronal group endowed more densely than other anterior horn neurons with serotonin-like immunoreactive fibers was recognized in the anterior column of lumbar segments L1-L2. At the same time, this small nucleus was shown to contain the motoneurons innervating the cremaster muscle by means of retrograde labelling with DAPI. It is tentatively suggested that the bulbospinal descending serotonin system is particularly intimately connected with the function of the cremaster muscle.

Animals↗

Cerebral pial arterial innervation with special reference to GABAergic innervation.

Glutamic acid decarboxylase (GAD)-immunoreactive (I) nerve fibers were observed to run parallel to other autonomic nerve fibers, especially vasoactive intestinal polypeptide (VIP)- and calcitonin gene-related peptide (CGRP)-I nerve fibers at the light microscopic level. At the ultrastructural level, GAD-immunoreactivities co-localized with CGRP immunoreactivities in nerve terminals, but not with choline acetyltransferase, VIP, tyrosine hydroxylase and neuropeptide Y immunoreactivities. GAD immunoreactivities were observed in the trigeminal ganglion, some of which were co-localized with CGRP-immunoreactivities. In the proximal portion of the internal carotid artery, GAD-I adventitial ganglion cells were observed and some were also immunoreactive for CGRP. These results strongly suggest that the origin of GABAergic innervation of the major cerebral pial arteries of the cat is mainly in the trigeminal ganglion, and partly in the adventitial ganglia of the internal carotid artery.

Animals↗

Catecholamine innervation of cervical dendrite bundles: possible phrenic nucleus innervation.

The catecholaminergic innervation of three recently described dendrite bundles (midline, central and lateral) in the cervical spinal cord of the adult Long-Evans hooded rat [41] was examined using Golgi impregnation, fluorescence histochemistry for catecholamines, and cholinesterase histochemistry. The midline and lateral bundles were similar in appearance to those described by the Scheibel and Scheibel [50,51], while the central bundle, present in the region of the phrenic nucleus, has not been described previously. Analysis of Golgi-Cox impregnated horizontal sections demonstrated the presence of fine varicose fibers within all three bundles. These profiles entered the bundles at right angles, either singly or within small transverse dendritic subunits, then turned in a rostral or caudal direction, and coursed adjacent to dendrites of motoneurons in the bundles. Catecholamine histofluorescence in horizontal sections revealed abundant varicosities within all three bundles, similar in size and appearance to the varicose fibers seen in Golgi-Cox impregnated sections. Catecholamine fibers entered the dendrite bundles at right angles then turned rostrally or caudally and coursed horizontally within the bundles. Varicose fluorescent profiles formed pericellular rings around the motoneurons and linear profiles adjacent to the dendrites, sometimes outlining the entire proximal portion of primary dendrites. Catecholamine fibers entered the dendrite bundles at right angles then turned rostrally or caudally to course adjacent to the dendrites within the bundles. Cholinesterase histochemistry in alternate sections revealed staining of motoneurons and their dendrites, and confirmed the location of the catecholamine varicosities within the motoneuron dendrite bundles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Ultrastructure of vesicourethral innervation. II. Postganglionic axoaxonal synapses in intrinsic innervation of the vesicourethral lissosphincter: a new structural and functional concept in micturition.

The interrelationships of postganglionic axons in intrinsic neuroplexuses of the vesicourethral lissosphincter ('internal sphincter') were studied ultrastructurally in the cat and rat of both sexes. Direct axoaxonal contracts between cholinergic and adrenergic axons were common in preterminal axon bundles and at neuroeffector junctions. Similar contacts between 2 cholinergic or 2 adrenergic axons were less frequent. Most contacts were ultrastructurally simple, but some had focal areas of very close axolemmal apposition, and some were focally specialized as bona fide chemical synaptic complexes. The axoaxonal contacts are introduced as a complex interaxonal synaptic system that chemically, and possibly also electrically, modulates neurotransmission in postganglionic axons innervating the lissosphincter, presynaptically (prejunctionally) at the infraganglionic level, especially by reciprocal cholinergic/adrenergic axonal interaction. This synaptic system is introduced as a potential, hitherto unrecognized, site of action of autonomic drugs, and as a key factor in the neural mechanism controlling continent closure of the lissosphincter during bladder filling, its opening to initiate and maintain voiding, and its closure to terminate the micturition cycle.

Animals↗

Motor innervation, motor unit organization and afferent innervation of m. extensor digitorum communis of the baboon's forearm.

1. One hundred and fifty efferent axons innervating m. extensor digitorum communis (EDC) were isolated in filaments of C7 and C8 ventral roots of baboons. Conduction velocities were measured antidromically by stimulating the muscle nerve and recording from the filaments, and fell into two groups: a fast (49-84 m/sec) and a slow (22-41m/sec), presumably fusimotor group. The threshold for these latter axons exceeded the strength needed to elicit the maximal motor twitch.2. Stimulation of ventral root filaments containing slow axons produced no contractile tension in EDC.3. Stimulation of ventral root filaments containing fast-group axons elicited all-or-nothing twitches of motor units of EDC. The twitch tensions of 66.3% of the units were < 2.0 g wt.; only 8.7% were > 5.0 g wt. Tetanus-twitch ratios were 1.4-4.7 in a sample of 14 units. Contraction times were between 15 and 35 msec in 97% of the units. There was no correlation between contractile properties and axonal conduction velocity.4. Afferent volleys from the stimulated EDC nerve were recorded from C6 or C7 dorsal roots. The threshold was below the threshold for a just-detectable motor twitch in ten out of eleven baboons. Conduction velocity of the earliest component of the muscle afferent volley was 67-83 m/sec.5. The conduction velocities of twenty-eight spindle afferents, identified by their responses to linear stretches of EDC and by their unloading by maximal twitches, were all < 70 m/sec. Higher dynamic sensitivity tended to be associated with higher conduction velocity.

Journal Article↗

Components of sympathetic innervation of the rat thymus during late fetal and postnatal development: histofluorescence and biochemical study. Sympathetic innervation of the rat thymus.

This study was performed in order to investigate development of sympathetic innervation in the rat thymus. To achieve this aim histofluorescence and biochemical methods were used. The histofluorescence method revealed the presence of sympathetic nervous profiles in this organ for the first time on day 18 of gestation. The density of these profiles and intensity of their fluorescence increased progressively during late embryonal and postnatal development of the organ. In the outer cortex of adult thymus the sympathetic nervous profiles were found mainly in apposition to thymocytes, while in deeper cortex and medulla they were revealed adjacent to thymic epithelial cells. These nervous profiles were also found in close association with thymic autofluorescent cells, which density increased during the thymic postnatal development. Using the fluorometric method the concentrations of neither noradrenaline (NA) and dopamine (DA) nor serotonin (5-HT) were measurable until day 19 of embryogenesis. Their content increased during the postnatal development. The patterns of NA and DA increase during the postnatal development were almost identical, while the pattern of 5-HT increase was quite different. The present results indicate that DA might also be one of the transmitters of the thymic sympathetic nerve supply, as well as that the transmitters of that system can be involved in the regulation of activity of thymic epithelial and autofluorescent cells, but also in the modulation of T cell maturation.

Adrenergic Fibers↗

[Gaba innervation of serotonergic neurones innervating the thoracic marrow of the rat. Immunocytochemical and autoradiographic combination after retrograde axonal transport with tritiated serotonin ].

Anatomical relationship between GABA terminals and serotonergic neurons that innervate the thoracic spinal cord was studied using combined methods: autoradiography following (3H) 5-HT retrograde transport and immunocytochemistry for GABA. Following (3H) 5-HT injections into the thoracic spinal cord, serotonergic neurons of raphe pallidus and magnus were specifically radiolabelled. At optic and electron microscopic levels, radiolabelled cells of raphe magnus and pallidus were in contact with GABA immunoreactive pre-synaptic nerve terminals. Some radiolabelled cell bodies were contacted by both GABA immunoreactive and immunonegative terminals. These results indicate the existence of a direct GABAergic input onto the medullary serotonergic neurons projecting to the thoracic spinal cord and suggest both GABAergic and non-GABAergic regulation of these serotonergic neurons. Thus, combination of both a specific tracing technique and immunocytochemistry offers considerable advantages of specificity and sensibility for the study of interrelationship between chemically defined neuronal pathways and/or of transmitter co-existence.

Animals↗

[Histochemical and ultrastructural studies of the innervation of the lymph-vessel and blood-vessel wall. 1. Adrenergic innervation].

The adrenergic innervation of the lymph vascular wall was studied by means of the Falck fluorescence histochemical tecnique and electron microscopy with Tranzer and Richards' histochemical tecnique. The lymph vessels wall, compared with that of blood vessels, shows very few adrenergic nerve fibers located in the adventitia outside the smooth muscle cells. The possible role of the nervous system in the motor control of the lymph vessels is discussed.

Adrenergic Fibers↗

[Histochemical and ultrastructural studies of the innervation of the lymph-vessel and blood-vessel wall. II. Cholinergic innervation].

Using the Acetylcholinesterase (AChE) tecnique applied to light and electron microscopy, was observed that the lymph vascular wall shows very few and inconstant AChE-positive fibers. The cholinergic fibers run prevalently longitudinal in the perivascular connective tissue, only brief segments show a loose network. The results are discussed and compared with blood vessels innervation.

Animals↗