Vesicles in one type of mouse brain neuron hold about how many dopamine molecules on average?

1. Miniaturised probes can detect dopamine in very small amounts, allowing direct measurement inside single vesicles. 2. Those measurements give an average of 30,000 dopamine molecules per vesicle in one type of mouse brain neuron. 3. In molar terms that is about 5 x 10^-20 mol, or 50 zmol. 4. Drug therapies were found to change this average by up to three-fold in either direction. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.1 Formula Mass and the Mole Concept_