What are reciprocal inhibitory synapses? Quoting Kandel's _Principles of Neural Science_ , 2013, > Amacrine cells generally receive excitatory signals from bipolar cells at glutamatergic synapses. Some amacrine cells feed back directly to the presynaptic bipolar cell at a _reciprocal inhibitory synapse._ Some amacrine cells are electrically coupled to others of the same type, forming an electrical network much like that of the horizontal cells. (Page 593) I tried searching for what a reciprocal inhibitory synapse is but could not find any relevant information.

It might be better understood if written with a comma as:

> reciprocal, inhibitory synapse

though the rules for this comma usage in English might discourage this because writing "inhibitory reciprocal synapse" doesn't sound quite right. I would say the author wrote it correctly even though it is not perfectly clear.

In this context, they are separate adjectives describing the synapse: inhibitory, because it suppresses firing, and reciprocal because Cell A gives input to Cell B, and Cell B also gives input to Cell A (where Cell A is the amacrine cell and Cell B is the bipolar cell).

The word reciprocal in this context is the adjective definition of the word reciprocal:

> given, felt, or done in return.

Note that it isn't the synapse itself that is reciprocal or in both directions, but that the _cells_ have a reciprocal relationship.