摘要:

AbstractBromocriptine, lergotrile, lisuride, metergoline, and the Sandoz ergot derivatives 25–397, 29–712, and 29–717 have been tested for their ability to inhibit the synaptic receptor binding of spiroperidol, 5‐hydroxytryptamine (5‐HT), d‐lysergic acid diethylamide (LSD), quinuclidinyl benzilate (QNB), WB.4101, and γ‐aminobutyric acid (GABA). Only GABA binding was not affected, and QNB binding was decreased only by lergotrile and metergoline at high concentrations. The most potent inhibitors of the other ligands were bromocriptine and lisuride for spiroperidol (1–2 nM), metergoline for 5‐HT (29 nM), lisuride for LSD (15 nM), and lergotrile for WB.4101 (17 nM). The direct receptor effects of the ergot derivatives in vitro may contribute to understanding their in vivo effects on behavior and in predicting their therapeutic potential in neurological and neuroe

ISSN:0360-4012    

DOI:10.1002/jnr.490060102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractFunctional neural mapping by14C‐deoxyglucose autoradiography in adult rats has shown that increases in neural metabolic rate that are coupled to increased neurophysiological activity are more evident in axon terminals and dendrites than neuron cell bodies. Regions containing architectonically well‐defined concentrations of terminals and dendrites (neuropil) have high metabolic rates when the neuropil is physiologically active. In neonatal rats, however, we find that regions containing well‐defined groupings of neuron cell bodies have high metabolic rates in14C‐deoxyglucose autoradiograms. The striking difference between the morphological appearance of14C‐deoxyglucose autoradiograms obtained from neonatal and adult rats is probably related to developmental changes in morphometric features of differentiating neurons, as well as associated changes in type and locus of neural work

ISSN:0360-4012    

DOI:10.1002/jnr.490060103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe nerve growth factor protein (NGF) has been identified by biological assay and rocket immunoelectrophoresis in media conditioned by monolayers of mouse S‐180 sarcoma cells, a transformed cell line of salivary gland origin. By utilization of a purification procedure designed to enrich for acid‐dissociable, high‐molecular‐weight complexes similar to the 7S‐NGF isolated from male mouse submaxillary gland, it has been determined that a significant portion of mouse sarcoma NGF is initially present as a complex at neutral pH with a molecualr weight indistinguishable from that of 7S‐NGF. At pH 4.0 the mouse sarcoma NGF complex dissociates, and the active subunit can be isolated as a species with a molecular weight of less than 40,000. The induced dissociation at pH 4.0 of the mouse sarcoma NGF high‐molecular‐weight complex, as well as the complex's behavior in isoelectric focusing and sucrose gradient sedimentation is consistent with the hypothesis that 7S‐NGF is packaged as a subunit containing protein intracellularly prior to secretion into the extracellular space. Moreover, the stability of the mouse sarcoma NGF complex at dilute concentrations is similar to that reported for the purifi

ISSN:0360-4012    

DOI:10.1002/jnr.490060104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractK+‐sensitive liquid ion exchange electrode systems respond with a slow potential change to acetylcholine, choline, anticholinergic drugs, biogenic amines, and glutamic acid. The response threshold has been defined, and in most cases it is at extremely low concentrations (10−7–10−;5M). The direction of the potential change varies, but in most instances it is additive to that produced by external K+. The K+electrode system is further sensitive to decreasing pH, within a narrow and possibly physiological range of pH. These findings suggest that small measured changes in extracellular K+are biased by the chemosensitivity of the liquid ion exchange electrode system to some compounds of physiological imp

ISSN:0360-4012    

DOI:10.1002/jnr.490060105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractExtracellular recording and iontophoresis techniques were used to study the interactions of the trace amine, p‐tyramine (p‐TA) with putative neurotransmitters on single neurones in the cerebral cortex and caudate nucleus of the rat. p‐TA, when applied with weak iontophoretic currents which did not result in any change in neuronal firing rate, caused a pronounced potentiation of depressant responses to iontophoretically applied dopamine (DA). Depressant responses of cortical neurones to noradrenaline were also markedly potentiated by weak background applications of p‐TA. This potentiating action of p‐TA was related to the amount of the trace amine applied and was apparently specific for catecholamines, since depressant responses to 5‐hydroxytryptamine and γ‐aminobutyric acid were unaffected. Excitatory responses to iontophoretically applied glutamate were also unaltered by weak applications of p‐TA. Excitatory responses of most neurones to acetylcholine (ACh) were also unaffected by p‐TA in the cortex and caudate nucleus. However, responses to ACh of a small number of cells in both brain areas were reduced in size during weak applications of p‐TA. It is suggested that p‐TA may act as a modulator of neurotransmission, particularly that mediated by DA in the

ISSN:0360-4012    

DOI:10.1002/jnr.490060106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe ontogenesis of neuropeptide degrading enzymes was studied in the mouse brain, from the 10th gestational day up to adulthood. Two activities were followed: the pyroglutamate aminopeptidase and the post‐proline cleaving enzyme, using either TRH or specific fluorogenic peptides as substrates. In the hypothalamus as well as in cerebral hemispheres, the specific activities of both enzymes was highest on the 13th fetal day and decline thereafter until the 20–22nd post‐natal day, with a plateau around birth. In contrast, a classical peptidase, the leucyl‐arylamidase increased only in fetal life, and reached the adult level befor

ISSN:0360-4012    

DOI:10.1002/jnr.490060107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe relationship between induction of glutamine synthetase activity by dexamethasone and binding of the steroid to cytosolic glucocorticoid receptors was examined in sensitive C6 and resistant C6H glial cell cultures.Glutamine synthetase activity increased 3–4‐fold when C6 cultures were exposed to 7.6 × 10−6M dexamethasone. This inductive response was reversible, dose‐dependent (ED50∼ 2 × 10−8M), required de novo protein and RNA synthesis, and was elicited only by glucocorticoid steroids. Progesterone, but not epicortisol, antagonized the dexamethasone‐induced enzyme increase. In contrast, only a slight inductive effect was observed in dexamethasone‐treated C6H cells.Competitive binding assays demonstrated that specific binding of [3H]‐dexa‐methasone to cytosolic receptors was also dose‐dependent. The ED50was ∼ 10−8M for both C6 and C6H cells. Scatchard analysis revealed that each C6 cell contained ∼10,800 receptor sites and that the equilibrium dissociation constant (Kd) was 4.5 × 10−9M. Each C6H cell possessed ∼ 12,200 sites, and the Kdwas 6.7 × 10−9M. Unlabeled dexamethasone and cortisol (but not epicortisol) competed effectively with [3H]‐dexamethasone for binding to cytosolic receptor sites and nuclear sites of both cell types.These results suggest that induction of glutamine synthetase activity in dexamethasone‐treated C6 cells is a glucocorticoid‐directed response. Since C6H cells are refractory in this regard but contain functional cytosolic receptors which interact with cell nuclei, the basis for their resistance appears to involv

ISSN:0360-4012    

DOI:10.1002/jnr.490060108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractSpleen leukocytes from rats and mice immunized against mouse 2.5S nerve growth factor (NGF) and peripheral blood leukocytes from rabbits hyperimmunized against the same antigen were fused with the mouse plasmacytoma P3 × 63Ag8. Hybridomas were screened by immunological assays (microcomplement fixation test and solid phase radioimmunoassay) for production of antibodies that reacted with NGF. Significant variations were seen between culture fluids from different hybrid cells. In addition, most but not all hybridoma antibodies that reacted immunologically with NGF prevented neurite outgrowth from 8‐day chick embryo sensory ganglia explants after binding to NGF. These results suggest that the hybridoma antibodies produced by the different clones react with different antigenic sites on the NGF molecu

ISSN:0360-4012    

DOI:10.1002/jnr.490060109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractShort‐term (15 minutes) in vitro exposure to kainic acid (KA), a rigid structural analog of L‐glutamic acid (Glu), caused two morphologically distinct neuronal lesions in retinas of several species. In rabbit retina, one type of lesion was characterized by rapid swelling after exposure to low concentrations of KA (10−4M). This lesion was observed in elements of both plexiform layers and, more specifically, in cell bodies and neurites of horizontal cells that contact cones. A few cell bodies from the amacrine cell layer showed some limited swelling. The swelling was completely blocked when sodium was removed from the incubation medium. The second type of lesion was generally seen after longer exposures of after exposure to higher concentrations of KA and was evidenced by degeneration of neurons in the amacrine and ganglion cell layers. One exception was noted in that a few cells from the ganglion cell layer degenerated even under low exposure conditions. The second type of lesion was not blocked by removal of sodium ions. Photoreceptor cells appeared resistant to all effects of KA. The results suggest that a correlation may exist between certain KA‐induced lesions of the retina and putative glutamoreceptive neurons. At the same time, the two types of retinal lesions produced by KA are morphologically and chemically differentiable and may be useful in elucidating the differences between specific, Glu‐related toxicity and nonspecific toxic

ISSN:0360-4012    

DOI:10.1002/jnr.490060110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractContacts between horizontal and bipolar cells are described in the retina of the teleost Eugerres plumieri. A single, long expansion observed in the external cone horizontal cells makes contact by means of a terminal button with the cell body of a bipolar. It represents the only contact between this class of horizontal cell and the bipolar soma. On the other hand, the medial and internal cone horizontal cells and the rod horizontal cells, which lack such a single, long expansion, display instead numerous short and fine expansions that terminate by means of a terminal knob on a bipolar cell body. The bipolar‐destined, short expansions of the rod horizontal cell make contact with large bipolar cell bodies, whereas corresponding short expansions of cone horizontal cells contact small bipolar cell bodies.It is suggested that the ascending horizontal cell process forms presynaptic terminals in the photoreceptor triad complex, and that the single, long and the multiple, short bipolar‐destined expansions are postsynaptic to the bipolar cell b

ISSN:0360-4012    

DOI:10.1002/jnr.490060111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY