| Abstract: | Guinea-pig taenia coli preprations were pre-incubated in 3H-adenosine and the overflow of 3H-compounds to a superfusing medium was measured during transmural field stimulation in the presence and absence of tetrodotoxin. The fractional overflow of 3H-compounds on stimulation of taenia coli pre-incubated in 3H-adenosine at 10(-7) M was greater than after incubation at 10(-5) M. About half of the releasable store was blocked by tetrodotoxin. It is proposed that at lower concentrations, there is selective loading of a releasable store, while at higher concentrations thare is a greater loading of non-releasable stores, and that neuronal stores account for about 33% of the 3H-compounds released by transmural stimulation. |
