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A Wanaka

Publications and source records attributed to A Wanaka.

87 records · Page 5Linked to original sources
PubMed1988

Immunohistochemical demonstration of beta-adrenoreceptor in the rat brain--with reference to the central control of blood pressure.

Using anti-beta 2-adrenoreceptor antibody, we examined immunohistochemically the localization of adrenoreceptor in the rat central nervous system at both lightmicroscopic and electronmicroscopic level. In the areas which are known to be involved in the control of blood pressure, such as the hypothalamus, the nucleus of the solitary tract and the locus coeruleus, there were a number of adrenoreceptor-like immunoreactive (ADR-IR) structures. They were mainly associated with cellular surface of the neuron. However, those localized within the cytoplasm or the nerve fiber were also observed. Immunoelectron microscopic analysis revealed that the ADR-IR structures were associated with post-synaptic density and cytoplasmic organella (endoplasmic reticulum, vesicle). Ultrastructural feature of the ADR-IR fiber was characterized by the synaptic vesicles with immunoreaction products. In addition, we detected that the running pattern of the ADR-IR fibers was often quite similar to that of tyrosine hydroxylase-immunoreactive (i.e. catecholaminergic) fibers. These findings suggest the presence of the presynaptic autoreceptor. In the present study, we have clearly demonstrated the cellular and subcellular localization of adrenoreceptors in the areas related to blood pressure control immunocytochemically. These results suggest the immunocytochemical method should be quite useful for further investigation of the CNS control of blood pressure.

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PubMed1987

Corticotropin-releasing factor-like immunoreactive nerve fibers in the rat superior cervical ganglion and their fine structures.

The existence of nerve fibers containing corticotropin-releasing factor (CRF)-like immunoreactivity (CRFI) in the rat superior cervical ganglion (SCG) was demonstrated by using immunocytochemistry. They were found to be extrinsic in origin, because no CRFI neurons were seen in the SCG and decentralization resulted in the disappearance of CRFI fibers in the SCG on the operated side. These findings were also confirmed by immunoelectron microscopic analysis; CRFI fibers contained a number of small clear synaptic vesicles but were devoid of large granular and agranular vesicles. These morphological characteristics are identical to those of the preganglionic fibers. The present immunoelectron microscopic analysis revealed that most of the CRFI fibers in the SCG make synaptic contact predominantly with the dendrites of the principal cells, partly with their somas and rarely with a non-CRFI terminal. Thus, the present study provides direct morphological evidence that CRF directly influences the function of the principal cells of the SCG and that CRFI fibers are preganglionic.

Animals↗
PubMed1987

Two discrete enkephalinergic neuron systems in the superior cervical ganglion of the guinea pig: an immunoelectron microscopic study.

Leucine-enkephalin (L-ENK)-like immunoreactive (L-ENKI) structures in the superior cervical ganglion (SCG) were first examined by using immunoelectron microscopy. L-ENKI neurons formed cell clusters and were small. They were filled with large granular or agranular vesicles and small electron lucent vesicles, and had nuclei that lacked a nucleolus. Since these morphological characteristics are identical to those of the small intensely fluorescent (SIF) cells, L-ENKI cells seemed to be a kind of SIF cell. Two types of L-ENKI fibers were identified, a large type filled with large granular or agranular vesicles and a small type filled with small electron lucent vesicles. The large fibers were located near the L-ENKI perikarya and often could be traced directly to the soma. These fibers remained intact after decentralization of the SCG. These findings indicate that the large L-ENKI fibers are processes of L-ENKI SIF cells. The fibers showed a close apposition to the blood vessels and rarely formed synaptic contact with dendrites of the principal cells. On the other hand, the small L-ENKI fibers were found to originate outside the SCG, because they disappeared after decentralization of the SCG. These L-ENKI fibers frequently formed synaptic contact with the dendrites of the principal cells. Thus, the present study demonstrated the presence of two discrete L-ENKI neuron systems in the SCG of the guinea pig, one an intrinsic SIF system and the other an extrinsic L-ENKI system.

Animals↗
PubMed1987

Distribution of cholinergic neurons and fibers in the hypothalamus of the rat using choline acetyltransferase as a marker.

The distribution of choline-acetyltransferase-like immunoreactive structures in the rat hypothalamus and preoptic area was examined by using avidin-biotin immunocytochemistry. We found that the hypothalamus is richly innervated by the cholinergic neuron system. Sites containing cholinergic neurons of varying density were: medial and lateral preoptic areas, septohypothalamic nucleus, median preoptic area, lateral hypothalamus including the perifornical area, anterior hypothalamic nucleus, arcuate nucleus, dorsomedial hypothalamic nucleus, posterior hypothalamic nucleus, dorsal and ventral premammillary nuclei, neuropil mediodorsal to the anterior hypothalamic nucleus, neuropil ventral to the anterior hypothalamic nucleus and ventromedial hypothalamic nucleus, neuropil between lateral hypothalamus and ventromedial hypothalamus, and neuropil between dorsal premammillary nucleus and posterior hypothalamic nucleus. There were also many varicose and non-varicose fibers in the preoptic area and hypothalamus. Two kinds of varicose fibers, one with strong immunoreactivity and the other with weak immunoreactivity, were seen. Non-varicose fibers were also detected in the optic chiasma and habenulo-interpeduncular tract. These fibers were passing fibers.

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PubMed1987

Immunocytochemical localization of the choline acetyltransferase containing neuron system in the rat lower brain stem.

This distribution of choline acetyltransferase (CHAT) immunoreactivity (CHAT-I) in the rat lower brain stem was analyzed using a highly sensitive avidin-biotin immunocytochemical method and 3-amino-9-ethyl-carbazole visualization. A much wider and more abundant distribution of CHAT-I structures in the lower brain stem was demonstrated than in earlier studies. The following areas were newly identified as areas rich in CHAT-I fibers: the interpeduncular nucleus, medial geniculate body, central gray matter of pons, pontine nucleus, parabigeminal nucleus, dorsal tegmental nucleus of Gudden, lateral trapezoid nucleus, inferior colliculus, dorsal and ventral cochlear nuclei, medial and lateral vestibular nuclei, reticular formation of medulla oblongata, and gelatinosa of caudal trigeminal spinal tract nucleus. In addition to the areas in which they have been known to exist, CHAT-I perikarya were found in the caudal portion of substantia nigra pars reticulata, the area between trigeminal motor nucleus and superior olivary nucleus, the medial and spinal vestibular nucleus, prepositus hypoglossal nucleus, raphe magnus and obscurus, ventromedial portion of solitary tract nucleus and its just ventral reticular formation, and caudal trigeminal spinal tract nucleus.

Animals↗
PubMed1986

A new method for producing a specific and high titre antibody against glutamate using colloidal gold as a carrier.

Antiserum against the glutamate was developed using colloidal gold as a carrier for the antigen. Glutamate was bound directly to colloidal gold without using cross-linking reagents such as glutaraldehyde, formaldehyde, or carbodiimide. Repeated injection of the colloidal gold-glutamate complex into the rabbit yielded a specific, high titre antiserum. Specificity was verified by radioimmunoassay and histochemically with absorption controls. The antiserum immunohistochemically detected numerous glutamate-containing neurons in the rat brain.

Animals↗
PubMed1986

Two distinct calcitonin gene-related peptide-containing peripheral nervous systems: distribution and quantitative differences between the iris and cerebral artery with special reference to substance P.

The present study first shows that calcitonin gene-related peptide(CGRP)-like immunoreactive (CGRPI) nerve fibers in the cerebral arteries contained substance P (SP) and originated from small- to medium-sized CGRPI cells exhibiting SP immunoreactivity (SPI) in the trigeminal ganglion. The iris contained CGRPI/SPI-costorage nerve fibers and many CGRPI fibers lacking SPI. These fibers originated from large CGRPI cells lacking SPI in the trigeminal ganglion. The heterogenous subpopulations of CGRPI fibers in the iris suggest that CGRP is involved in a variety of functions in this structure.

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PubMed1986

Origins and distribution of calcitonin gene-related peptide-containing nerves in the wall of the cerebral arteries of the guinea pig with special reference to the coexistence with substance P.

The origins and overall distribution of calcitonin gene-related peptide-like immunoreactivity (CGRPI) in the wall of the cerebral arteries were investigated in the guinea pig by using whole-mounts. Two types of CGRPI fibers were seen; one forming dense fiber bands, located among the periadventitial nerves, and the other forming a meshwork. CGRPI fibers in the periadventitial nerves often leave these nerves to form a meshwork, of a density that varies according to the diameter or location of the blood vessel. The present study showed that CGRPI fibers in the walls of the carotid arterial system originated from the trigeminal ganglion, and those in the vertebrobasilar arterial system from other origins besides the trigeminal ganglion. We also examined the coexistence of this peptide with substance P-like immunoreactive (SPI) structures in a single neuron system. Double staining immunocytochemistry showed that the patterns of the running of CGRPI and SPI fibers in the wall of the cerebral arteries were similar, and this method also demonstrated the presence of neurons containing both CGRPI and SPI structures in single cells of the trigeminal ganglion, which is the major origin of these fibers in the cerebral arteries.

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PubMed1985

Fine structure of peptidergic and catecholaminergic nerve fibers in the anterior cerebral artery and their interrelationship: an immunoelectron microscopic study.

This study shows (1) the ultrastructure of vasoactive intestinal polypeptide (VIP)-, substance P (SP)-, and neuropeptide Y (NPY)-containing nerve fibers in the walls of the cerebral arteries and (2) the relationship between these peptidergic (VIP, SP, and NPY) and catecholaminergic (CA) nerve terminals by immunohistochemistry combined with false transmitter (5-hydroxydopamine) histochemistry under the electron microscope. VIP-, SP-, and NPY-like immunoreactivity (VIPI, SPI, and NPYI) were found diffusely in the axoplasm and around the small clear vesicles in the nerve terminals. In a few cases, SPI was found within the large vesicles. Most of the VIPI terminals were ensheathed by the cytoplasm of the Schwann cells together with CA terminals, identified as those with a number of small granulated vesicles. In some cases, they were directly apposed to the smooth muscle cells at a distance of about 100 nm. SPI terminals were frequently solitary but about 30% were located together with CA and other (neither SPI nor CA) terminals ensheathed by Schwann cells, directly apposed to the smooth muscle cells at a distance of about 100 nm. On the other hand, NPYI terminals were also identified as CA terminals, indicating the coexistence of these two substances. These findings suggest a close interrelationship between peptidergic and CA nerve terminals in the neurogenic control of cerebral blood vessel function.

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PubMed1985

The effect of isosorbide dinitrate and isosorbide-5-mononitrate on prostacyclin (PGI2) and thromboxane A2 (TXA2) generation in rat and human arteries.

The mechanism by which nitrates produce relaxation of the vascular smooth muscle and anti-aggregatory effect on platelets has not been understood. Several reports have suggested that vasoactive prostaglandin generation may account for part of the pharmacological action of nitroglycerin. However, few studies have been reported that isosorbide dinitrate or its main metabolite, isosorbide-5-mononitrate, directly stimulates prostacyclin (PGI2) generation in blood vessels. We examined the effect of ISDN and 5-ISMN on PGI2 and thromboxane A2 (TXA2) generation in rat thoracic aorta and human thoracic aorta and coronary artery. The stimulation of PGI2 generation was dependent on the concentration of ISDN and the maximum PGI2 generation was effected by ISDN 5.0 ng/ml in both rat and human vessels. The ratio of peak to basal PGI2 generation was about 1.6 with rat thoracic aorta and about 1.6 with human thoracic aorta and about 1.3 with human coronary artery. On the other hand, TXA2 generation showed a smaller increase than that of PGI2 with ISDN used in the therapeutic dose range and 5-ISMN did not significantly affect PGI2 or TXA2 generation. Previous studies of the effect of cyclooxygenase inhibitor, for example indomethacin, on the vasodilating response to nitrates have given conflicting results. It is believed, however, that ISDN is partially, not wholly, associated with the hemodynamic and platelet antiaggregation effects due to vascular PGI2 generation, which may play a beneficial role in inhibiting coronary vasospasm during anginal attacks.

Aged↗
PubMedDate not supplied

The effect of the calcium antagonist nimodipine on the gerbil model of experimental cerebral ischemia.

The gerbil model was used to assess the therapeutic effects of the calcium antagonist nimodipine on cerebral ischemia. Transient cerebral ischemia was produced in each gerbil by bilateral common carotid occlusion of 10-, 15- or 20-min duration. Nimodipine (0.01 or 0.1 mg/kg) was administered intraperitoneally just before the carotid occlusion or 10-30 min after the removal of the arterial clips. Morbidity of each animal was evaluated using the stroke index, and the sum of stroke indices was calculated for evaluating the overall morbidity during a particular period of reperfusion. Mortality was observed for 24 hours after clip removal. Although, depending on the timing of the drug administration, the low-dose (0.01 mg/kg) nimodipine worsened the morbidity in the gerbils with 10-min ischemia, the high-dose (0.1 mg/kg) of the drug had a clear beneficial effect on the mortality associated with cerebral ischemia. These results are considered worthwhile for further trials to assess the usefulness of nimodipine as a therapeutic agent in the management of the acute ischemic stroke.

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