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This essay attempts to summarize some of the best evidence for the role of inositol trisphosphate as a second messenger in signal transduction processes. The following aspects are addressed in the essay: (a) The synthesis of inositol trisphosphate and other inositol lipids, (b) Receptor-phosphatidylinositol bisphosphate phospholipase C coupling and the N-ras protooncogene, (c) Inositol trisphosphate and intracellular calcium, (d) Cell growth and oncogenes, (e) Receptors linked to the phosphatidylinositol cycle, (f) Phototransduction and (g) Interactions between inositol trisphosphate and other second messengers.Abbreviations Cyclic AMP
Adenosine 3,5-cyclic monophosphate
- Cyclic GMP
Guanosine 3,5-cyclic monophosphate
- DG
sn, 1,2-Diacylglycerol
- EGF
Epidermal growth factor
- GDP
Guanosine diphosphate
- GTP
Guanosine triphosphate
- IP
Inositol 1-monophosphate
- IP2
Inositol 1,4-diphosphate
- IP3
Inositol 1,4,5-trisphosphate
- PA
Phosphatidic acid
- PDGF
Platelet-derived growth factor
- PI
Phosphatidylinositol
- PIP
Phosphatidylinositol 4-monophosphate
- PIP2
Phosphatidylinositol 4,5-bisphosphate
- PIP3
Phosphatidylinositol 3,4,5-trisphosphate
- PLC
Phospholipase C 相似文献
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C J Duncan C L Osborne J J Parsons K E McCall M J Jackson 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1988,90(2):459-460
1. Isolated amphibian hearts and pectoris cutaneous muscles were exposed either to DNP or to caffeine, thereby producing severe myofilament damage. 2. No accompanying change in sarcolemma permeability was detected by monitoring either CK or LDH release or Procion yellow entry in the heart, or by Procion entry in amphibian skeletal muscle. 3. The findings are in contrast with mammalian cardiac and skeletal muscles, and confirm that the pathways leading to myofilament degradation and to the breakdown in sarcolemma organization are separate. 相似文献
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The aim of this investigation was to study crypt fission, a process which may be instrumental in regulating crypt number in the intestine. Young Holtzman rats were killed at various times after parturition and samples of the small intestine and colon were removed and processed. A microdissection technique was used to separate crypts from other structures. Crypts were scored as normal or fissioning. The percentage of crypts in fission (PCF) reached peak values of 25% and 52% in the small bowel and colon, respectively, at 21 days post-parturition. From this time onward, the PCF dropped until the adult value of approximately 7% was reached in each site. During this same period, the number of crypts increased from 1.9 X 10(6) to 3.3 X 10(6) in the small bowel and 2.2 X 10(5) to 6.5 X 10(5) in the colon. Thus an inverse relationship between the percentage of crypts in fission and crypt number was found. Distribution of fissure heights in fissioning crypts did not change as the animal aged. The majority of the fissures were found in the lower 1/4 of the fissioning crypts. This suggests that as soon as the fissure extends beyond the stem cell zone, division into two crypts soon occurs. 相似文献
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A subunit of choleragen and an erythrocyte ADP-ribosyltransferase catalyze the transfer of ADP-ribose from NAD to proteins and low molecular weight guanidino compounds such as arginine. These enzymes also catalyze the hydrolysis of NAD to nicotinamide and ADP-ribose. The kinetic mechanism for both transferases was investigated in the presence and absence of the product inhibitor nicotinamide by using agmatine as the acceptor molecule. To obtain accurate estimates of kinetic parameters, the transferase and glycohydrolase reactions were monitored simultaneously by using [adenine-2,8-3H]NAD and [carbonyl-14C]NAD as tracer compounds. Under optimal conditions for the transferase assay, NAD hydrolysis occurred at less than 5% of the Vmax for ADP-ribosylation; at subsaturating agmatine concentrations, the ratio of NAD hydrolysis to ADP-ribosylation was significantly higher. Binding of either NAD or agmatine resulted in a greater than 70% decrease in affinity for the second substrate. All data were consistent with a rapid equilibrium random sequential mechanism for both enzymes. 相似文献
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GABA neurones in retinas of different species and their postnatal development in situ and in culture in the rabbit retina 总被引:3,自引:0,他引:3
Summary The localisation of GABA immunoreactive neurones in retinas of a variety of animals was examined. Immunoreactivity was associated with specific populations of amacrine neurones in all species examined, viz. rat, rabbit, goldfish, frog, pigeon and guinea-pig. All species, with the exception of the frog, possessed immunoreactive perikarya in their retinal ganglion cell layers. These perikarya are probably displaced amacrine cells because GABA immunoreactivity was absent from the optic nerves and destruction of the rat optic nerve did not result in degeneration of these cells. GABA immunoreactivity was also associated with the outer plexiform layers of all the retinas studied; these processes are derived from GABA-positive horizontal cells in rat, rabbit, frog, pigeon and goldfish retinas, from bipolar-like cells in the frog, and probably from interplexiform cells in the guinea-pig retina.The development of GABA-positive neurones in the rabbit retina was also analysed. Immunoreactivity was clearly associated with subpopulations of amacrine and horizontal cells on the second postnatal day. The immunoreactivity at this stage is strong, and fairly well developed processes are apparent. The intensity of the immunoreactivity increases with development in the case of the amacrine cells. The immunoreactive neurones appear fully developed at about the 8th postnatal day, although the immunoreactivity in the inner plexiform layer becomes more dispersed as development proceeds. The immunoreactive horizontal cells become less apparent as development proceeds, but they can still be seen in the adult retina.The GABA immunoreactive cells in rabbit retinas can be maintained in culture. Cultures of retinal cells derived from 2-day-old animals can be maintained for up to 20 days and show the presence of GABA-positive cells at all stages. In one-day-old cultures the GABA immunoreactive cells lacked processes but within three days had clearly defined processes. After maintenance for 10 days a meshwork of GABA-positive fibres could also be seen in the cultures. 相似文献
19.
Summary A monoclonal antibody against substance P was used for immunocytochemical staining of the central ganglia of the snail Helix aspersa and several peripheral tissues including the gut, reproductive system, cardiovascular system, tentacle and other muscles.Within the central ganglia many neurones, and many fibres in the neuropile and the nerves entering the ganglia, were stained for the SP-like material. The largest numbers of reactive cell bodies were in the pleural ganglia and on the dorsal surfaces of the pedal ganglia. A group of cells was also found, surrounding the right pedal-cerebral connective, that did not fluoresce, but were enveloped by reactive processes terminating directly onto the neurone somata.Specific staining was observed in all peripheral tissues examined and always appeared to be concentrated in nerve terminals. Most particularly these occurred in the heart and aorta, the pharyngeal retractor muscle and the tentacle. Although mostly present in muscular tissues, some fluorescence was also observed in the nervous layer surrounding the retina. The tentacular ganglion also contained immunoreactive cell bodies. 相似文献
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