Incorrect interpretations of radioactive labelling experiments with false transmitters.

Area of Science:

• Neuroscience
• Biochemistry
• Cell Biology

Background:

• Previous studies attempted to identify the subcellular origin of released neurotransmitters.
• These studies relied on comparing radioactivity ratios (14C/3H) of true and false transmitters.
• Comparisons were made between stimulated release and subcellular fractions.

Purpose of the Study:

• To evaluate the validity of different ratio methods for determining neurotransmitter subcellular origin.
• To identify the correct basis for comparing transmitter release and subcellular fractions.

Main Methods:

• Analysis of radioactivity ratios (14C/3H) in true and false transmitters.
• Comparison of these ratios between stimulated release and subcellular fractions.
• Evaluation of isotopic, pseudo-molar, and true molar ratios.

Main Results:

• Isotopic and pseudo-molar ratios were found to be unreliable for determining subcellular origin.
• Varying degrees of isotopic dilution render these ratios meaningless.
• The true molar ratio emerged as the only valid basis for comparison.

Conclusions:

• Previous methods using isotopic or pseudo-molar ratios can lead to incorrect conclusions.
• Accurate determination of neurotransmitter subcellular origin necessitates the use of true molar ratios.
• This finding refines methodologies in neurotransmitter research.