摘要:

The first step in olfactory transduction is the recognition of odor molecules by membrane bound receptors belonging to the superfamily of G-protein coupled receptors; other members of this family are involved in neurotrans- mission. Based on the considerable homology between individual members of this family, we have investigated the ability of well-known neurotransmitter antagonists to block the olfactory response. Adrenergic and muscarinic antagonists were found to block some odor induced currents (45–55%) with an IC50between 15 and 75 μM. By contrast, antagonists of glutamate and GABA receptors, which do not belong to this receptor superfamily, were ineffective. These results suggest that further pharmacological analysis may be useful for characterizing and classifying the family of odor receptors.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

C-foscontaining neurons were investigated in the trigeminal sensory nuclear complex and in the dorsal horns of the cervical spinal cord (C1-C2) of the rat after a chemical noxious stimulus was applied to the lower lip mucosa. Numerous labelled neuronal nuclei were detected in the dorsolateral area of the caudal half of the trigeminal nucleus interpolaris, and in Rexed's laminae I-II0of the dorsomedial area of the trigeminal nucleus caudalis and rostral C1. A fewc-fos-labefled neurons were observed in laminae IIiand V. NoFosexpression was detected in the trigeminal oral and principal nuclei.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Antiserum to haptenic [D-Ala2]deltorphin I (DADTI: Tyr-D-Ala-Phe-Asp-Val-Val-Gly±NH2), a highly selective ligand for δ opioid receptors, was produced in rabbits. By immunospot assay, the antiserum recognized 62.5 pmol DADTI but failed to react even with 4 nmol carrier protein of the immunogen. Although the antiserum reacted equally with an isomer [L-Ala2]deltorphin I, virtually no cross-reaction occurred with other analogues such as [D-Ala2]deltorphin II (Tyr-D-Ala-Phe-Glu-VaI-Val- Gly±NH2) and similar peptides lacking the C-terminal gly- cine amide. Therefore, the major epitope for immunore- cognition appeared to be in the C-terminal region which is known to be the specific domain for δ opioid receptor selectivity. Immunohistochemical study using this antiserum revealed positive neuronal structures in some specific systems of the mouse brain.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The cholinergic pedunculopontine tegmental area of the anesthetized rat was explored for single units responsive to somatosensory stimulation. Units projecting to the intralaminar thalamus were identified by antidromic stimulation. Approximately one half of the somatosensory units consisted of low threshold units responsive to light tapping and stroking; the others were high threshold mechanoreceptive units. Most receptive fields were tri- geminal and contralateral. These results suggest that somatosensory information is an important element in a subcortical system linking this area with the basal ganglia, superior colliculus and thalamus.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Since REM sleep deprivation was reported to increase the activity of acetylcholinesterase, an attempt was made to investigate whether the different forms of enzyme could be affected selectively. The flower pot method was used for deprivation and suitable control experiments were conducted. The bound and the soluble forms, if affected would show an increase or a decrease, respectively, on REM deprivation. The former is affected first in the pons while the latter in the medulla. The findings support the ponto- medullary cholinergic mechanism for the generation of REM sleep. Though there may be a possibility of conversion of the free to the bound form, the increase in the latter was more than the decrease in the former.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

During the investigation of visually evoked postsynaptic potentials (PSPs) of visual cortical neurons, we recorded cell activity under different levels of membrane potential. In some cases, however, dependence of these PSPs on the level of membrane polarization appears to be inconsistent with the conventional scheme. One disagreement was the reduction, instead of an increase, of excitatory potentials during hyperpolarization of the cell. The other point was that depolarization of the cell often leads to increase of the amplitude of both excitatory and inhibitory postsynaptic potentials. This inconsistency may suggest the involvement of voltage-dependent ion channels in generating PSPs to visual stimuli. A possible way of separating the excitatory and inhibitory components of the response by polarization of the cell in spite of the presence of voltage- dependent channels and possible implications of this mechanism in the visual cortex are discussed.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

When a part of an image is stabilized on the retina, the part fades to the same colour as its unstabilized surround.1,2The apparent colour of an empty field is therefore assumed to be equal to the colour of its borders.2Here, we will show that a similar phenomenon can take place even when the border of a centre field is still visible. A grey square patch with a black frame was surrounded by a coloured background. When the frame had such crossed disparity that the frame appeared in front of the patch, the colour of the patch became perceptually similar to that of the background, indicating that the colour of an empty field is not determined by the colour of its borders alone.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The effects of tri-iodothyronine (T3), which are known to affect cerebellar development, were tested on neuronal survival and differentiation of cultured cerebellar granule neurons. T3 in physiological concentrations increased both granule neuron survival after three days in culture and synaptic vesicle protein formation, as shown by immunostaining with antibodies against synaptophysin. Likewise, T3 increased the mRNA level for synapsin(I), but not that for GAP43 in granule neurons. Antibodies against microtubule associated protein Tau, which is expressed in developing neurites, showed that T3 also enhanced neurite formation.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The cellular localization of mRNAs encoding the low affinity NGF receptor (here referred to as LANR) and the putative high affinity receptor for NGF,trk, have been studied in the human foetal spinal and sympathetic ganglia, and spinal cord, usingin situhybridization. The receptor mRNAs were highly expressed in the spinal and sympathetic ganglia, with most but not all neurons expressing both LANR andtrkmRNA. Spinal nerve rootlets distal to the spinal ganglia expressed LANR but nottrkmRNA, confirming the presence of the low affinity receptor in developing Schwann cells. In the spinal cord, LANR mRNA was found throughout the medial and lateral motor columns while,trkmRNA was detected in scattered cells in the dorsal aspect of developing grey matter.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Kainate evokes a non-desensitizing membrane depolarization in neuropile glial cells of the leechHirudo med- icinalis.We measured membrane potential and intracellular pH, pH:, using double-barrelled pH-sensitive microelectrodes, and intracellular calcium, Ca2+i, using the change in fluorescence ratio of intracellularly injected fura-2, in these glial cellsin situ.20–50 μM kainate produced a depolarization of 18–28 mV and a decrease of pHiby 0.27 ± 0.07 pH units. Ca2+, increased by 306 ± 128 nM upon kainate, which could be inhibited by the non- NMDA antagonist CNQX. Glutamate (0.1 mM) also produced a fall in pH, and a rise in Ca2+i, which were however, much smaller. Quisqualate andN-methyl-D-aspartate had only small or no effects on membrane potential, pHior Ca2+i. It is concluded that leech neuropile glial cells have a kainate-type glutamate receptor, which mediate significant transients of intracellular H+and Ca2+.

ISSN:0959-4965    

出版商:OVID    

年代:1992

数据来源: OVID