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M Stocker

Publications and source records attributed to M Stocker.

46 records · Page 3Linked to original sources
PubMed1990

Alternative Shaker transcripts express either rapidly inactivating or noninactivating K+ channels.

Two members of the Shaker K+ channel family designated ShA2 and ShD2 were characterized in the Xenopus oocyte expression system. The predicted amino acid sequences of ShA2 and ShD2 differ only in the amino terminus, which is located intracellularly according to the present topological model of K+ channels. The differing amino termini have profound effects on the electrophysiological and pharmacological properties of the K+ channel. Most markedly, the nature of the amino terminus determines whether the K+ channel mediates rapidly inactivating or noninactivating K+ currents. It also affects the 4-aminopyridine, tetraethylammonium, and charybdotoxin sensitivities of the K+ channels. These results suggest that the amino terminus of Shaker proteins affects K+ channel structures on both sides of the membrane.

4-Aminopyridine↗
PubMed1989

Molecular basis of functional diversity of voltage-gated potassium channels in mammalian brain.

Cloning and sequencing of cDNAs isolated from a rat cortex cDNA library reveals that a gene family encodes several highly homologous K+ channel forming (RCK) proteins. Functional characterization of the channels expressed in Xenopus laevis oocytes following microinjection of in vitro transcribed RCK-specific RNAs shows that each of the RCK proteins forms K+ channels that differ greatly in both their functional and pharmacological properties. This suggests that the molecular basis for the diversity of voltage-gated K+ channels in mammalian brain is based, at least partly, on the expression of several RCK proteins by a family of genes and their assembly to homooligomeric K+ channels with different functional properties.

4-Aminopyridine↗
PubMed1988

Potassium channels expressed from rat brain cDNA have delayed rectifier properties.

Injection into Xenopus oocytes of RNA synthesized in vitro using the rat brain cDNA RCK1 as a template or nuclear injection of the cDNA results in the expression of functional potassium channels. These channels exhibit properties similar to those of the non-inactivating delayed rectifier channel found in mammalian neurons and other excitable cells.

4-Aminopyridine↗
PubMed1980

Increased kallikrein excretion in spontaneously hypertensive rats and its inhibition by 6-hydroxydopamine.

Urinary kallikrein excretion was studied in young, stroke-prone, spontaneously hypertensive rats (spSHR). Seven-week-old spSHR were found to excrete more kallikrein into the urine than normotensive Wistar Kyoto control rats (WKR). "Chemical sympathectomy", induced by 6-hydroxydopamine (6-OHDA) immediately after birth, resulted in normotensive blood-pressure levels and in a reduction of kallikrein in spSHR. In normotensive WKR, blood pressure and urinary kallikrein excretion were only slightly diminished by 6-OHDA. The results suggest a relationship between sympathetic activity and kallikrein excretion, being especially pronounced in spSHR, which have an elevated sympathetic activity.

Animals↗
PubMed1979

Production of antibodies against bradykinin.

High-titer antibodies against bradykinin were raised in rabbits. 2 different conjugates of bradykinin were used for immunization: bradykinin coupled to human serum albumin via 1,5-difluoro-2,4-dinitrobenzene and bradykinin coupled to edestin via 1-ethyl-3(3-dimethyl-aminopropyl)-carbodiimide. The sensitivity of the radioimmunoassay method is in the range of 1-50 pg of bradykinin. Cross-reaction of anti-bradykinin antisera occurred with kallidin and met-lys-bradykinin.

Animals↗
PubMed1978

Application of bradykinin radioimmunoassay for the measurement of urinary kallikrein activity rats.

Bradykinin radioimmunoassay was applied for the measurement of urinary kallikrein activity in rats. Antisera against bradykinin were raised in rabbits by injecting synthetic bradykinin coupled to human serum albumin via a difluorodinitrobenzene reaction. For radioimmunoassay a high titre antibody was used at a final dilution of 1:65000 to bind approximately 8,000 cpm of [125I]-tyrosine8-bradykinin. Standard curves were plotted from synthetic bradykinin samples (1--1000 pg). Kinins were generated by incubating partially purified kininogen with rat urine in the presence of kininase inhibitors. Bradykinin antiserum showed crossreaction with kallidin, met-lys-bradykinin and dog-kininogen. To eliminate interference of the kininogen with kinin radioimmunoassay, alcohol precipitation of the substrate was performed after incubation. Concentration of urinary kallikrein in rats showed no significant difference between day and night 12-hours-colllecting period. Total kallikrein excretion at night, however, was about twofold higher, correlating to a twofold higher urine volume during the night.

Animals↗