摘要:

WE describe quantitation of the absolute amounts of 5HT2Areceptor mRNA in various areas of human postmortem brain using a very sensitive and specific technique: competitive reverse transcription polymerase chain reaction (RT-PCR). With this procedure, we were able to show that the highest levels of 5HT2Areceptor mRNA are in cerebral cortical areas, i. e., Brodmann's areas 8, 9, 10, 18, 19, 22, 24, and 46, and that intermediate levels occur in the hippocampus, the amygdala, the nucleus accumbens, and the hypothalamus. Very low levels of 5HT2Areceptor mRNA were found in the cerebellum, the thalamus, the caudate, and the putamen. Our results confirm the heterogeneous distribution of 5HT2Areceptor mRNA in human postmortem brain and suggest that competitive RT-PCR is a highly sensitive and specific procedure for the quantitative measurement of 5HT2Areceptor mRNA expression. The study of 5HT2Areceptor mRNA in different brain areas will help clarify the regulation of 5HT2Areceptors at the transcriptional level in various neuropsychiatric diseases.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

NEURTURIN (NTN) belongs to a structurally related family of bioactive molecules which include glial cell-line derived neutrotrophic factor (GDNF) and perserphin (PSP). NTN exerts its effects through a multicomponent receptor system which include a receptor (GFRα-2) and the proto-oncogene c-RET. We report here the identification of three splice isoforms of the GFRα-2 receptors (GFRα-2a, GFRα-2b and GFRα-2c) by reverse transcription-PCR (RT-PCR). GFRα-2b is a novel splice variant. All three isoforms were found to be expressed in various adult murine tissues as well as in the brain of the newborn human. The identity of these isoforms were further confirmed by the isolation of the gene and the characterisation of the splice junctions.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

FIELD potential recordings were made from the dentate gyrus of urethane-anaesthetized rats in order to investigate the ability of 5 Hz stimulation to reverse long-term potentiation (LTP) induced by a high frequency tetanus. A 10 min train of 5 Hz was found to reverse LTP in a time-dependent fashion: as the interval between tetanus and 5 Hz was increased, LTP became progressively less susceptible to reversal. If 10 min or 30 min intervened between tetanization and 5 Hz stimulation, LTP was unaffected. These results indicate that dentate LTPin vivoexhibits a similar limited time window of vulnerability to reversal by low frequency stimulation to that previously reported in area CA 1in vitro.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE present study examined changes in the angiotensin type 2 (AT2) receptor mRNA level after carbachol exposure in PC12 cells. The AT2 receptor mRNA level increased 2-to 3-fold after 12–18 h of carbachol exposure (100 μM). The up-regulation of AT2 receptor mRNA was antagonized by atropine, which is a muscarinic receptor antagonist, thus suggesting that the increase in AT2 receptor mRNA is mediated via muscarinic acetylcholine receptors. This increase is blocked by NG-nitro-L-arginine-methylester, nitric oxide (NO) synthase inhibitor, and hemoglobin NO trap. Protein kinase C (PKC) inhibitors, H-7 and calphostin C, inhibited the carbachol-induced upregulation. In addition, a G kinase inhibitor, ODQ (1H-[1,2,4] oxadiazolo[4,3-a] quinoxalin-1-one), inhibited this increase. These findings suggest that the carbachol-induced increases in AT2 receptor mRNA is regulated by the activation of NO-cGMP and/or the PKC pathway.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

TUMOR necrosis factor-α(TNFα) was infused into the subarachnoid space of the rat rostral basal forebrain, which was previously defined as a prostaglandin (PG) D2-sensitive, sleep-promoting zone. TNFα increased the amount of slow-wave sleep (SWS), decreased that of paradoxical sleep (PS), and caused fever and anorexia. The TNFα-induced SWS enhancement, fever and anorexia were all blocked by co-infusion of diclofenac, a non-selective cyclooxygenase (COX) inhibitor, and by pretreatment with NS-398, a COX-2-specific inhibitor. In striking contrast, the TNFα-induced suppression of PS was not affected by the inhibitors. These results indicate that COX-2-mediated hyperproduction of PGs is critically involved in the enhancement of SWS, fever, and anorexia but not in the suppression of PS, caused by TNFα infused into the PGD2-sensitive zone.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

SYSTEMIC administration of lipopolysaccharide (LPS), a non-specific activator of proinflammatory cytokine release from macrophages, provokes sickness characterized by anorexia, soporific effects, and disturbances of locomotor activity and exploration. In addition, endotoxin treatment may provoke an anhedonic response. Assessment of anhedonia in appetitive paradigms, however, is compromised by the anorexia provoked by the treatment. The present investigation assessed the anhedonic effects of LPS on rewarding lateral hypothalamic brain stimulation. Using a simultaneous discrimination, current titration procedure in the assessment of intracranial self-stimulation (ICSS), it was found that acute systemic administration of LPS (50μg, 100μg or 200μg) reduced ICSS during the ascending sequence of current presentations, but had little effect on responding to a series of descending currents. In a parallel experiment, peripheral administration of LPS (100μg) increasedin vivodopamine (DA) efflux from the nucleus accumbens, a region thought to be involved in goal-directed responding to positively reinforcing stimuli. It is suggested that LPS alters ICSS in a manner different than that observed following stressor exposure or peripheral IL-2 treatment. Furthermore, LPS may engender an anhedonic effect (possibly secondary to sickness), and the decline of responding reflects the relation between the cost of responding given in the face of sickness and the reward received for responding.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The effects of two basic cysteine-rich lipid-binding proteins isolated from wheat seedlings, puroindoline-a and α1-purothionin, were studied on single frog myelinated axons stained with the fluorescent dye FM1-43 using confocal laser scanning microscopy. During exposure to either puroindoline-a or α1-purothionin (10 and 100 μM) a marked swelling of nodes of Ranvier was observed, provided NaCl was present in the external solution. It is suggested that these proteins increase the internal osmolality by forming pores in the axonal membrane and induce water influx to compensate for such an increase. Moreover, in the presence of α1-purothionin (100 μM), the intensity of the axonal staining with FM1-43 was increased. It is the first time, to our knowledge, that basic proteins containing domains of a cysteine-rich repeated motif are reported to produce swelling and water movements across neuronal cell membranes.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ELECTRIC brain responses were measured to infrequent tones that broke the frequency alternation of two tones, deviated in duration or violated both regularities (alter-nation and constant duration). Mismatch negativity (MMN) was elicited by both simple deviants with the duration-related MMN peaking ∼130 ms later than the alternation-related MMN. The double deviant elicited two successive MMNs. Thus violation of each regularity elicited a separate MMN, whereas previous studies showed that multiple temporally separate deviations from a single repetitive standard elicit one MMN only. These results suggest that the primary function of the MMN-generating process is more closely related to maintaining the representation of auditory regularities than to deviance detectionper se.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE ventral cochlear tract in the brain stem to pons was transected on one side in two groups of adult rats. In one group simple transection was performed, while in the other group tissue from embryos (E14–E16) was used to cover the lesion site. While rats receiving simple tran-section without transplantation showed no evidence of regeneration, in 30% of the rats receiving transplants of embryonic tissue the axons regrew beyond the transected site and regenerated into the denervated side and terminated at the normal targets. The present findings contradict the widely held view that the adult mammalian central auditory system cannot be restored following damage.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

SCHIZOPHRENIA is associated with an absence of the lateralizations that typify the human brain. Previous evidence emphasized structural changes, particularly reduced asymmetry in extension and surface of the planum temporale, although gross structural deviations occur only in a minority of patients. The present study describes an absence of lateralization on a robust functional measure that characterized schizophrenia patients: healthy subjects but not schizophrenics displayed a contralateral left-hemispheric dominance of the auditory evoked magnetic field to right-ear auditory stimulation. Absence of contralateral dominance in response to auditory stimuli among schizophrenia patients may indicate a failure to establish unequivocal left-hemispheric dominance of the phonological loop as hypothesized by Crow.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID