NERVOUS MECHANISM CONTROLLING PIGMENT AGGREGATION IN FUNDULUS MELANOPHORES

1. 1. The mechanism of nervous control of melanin movements in melanophores was studied, using the isolated split tail-fin preparation of the killifish, Fundulus heteroclitus. 2. 2. A single electrical shock to nerves caused moderate pigment aggregation in a melanophore. The response was not of the all-or-none type, suggesting that more than two nerve fibers control pigment aggregation in the cell. 3. 3. The presence of antidromic responses was confirmed, indicating that some nerves which have synaptic contact with one melanophore extend peripherally to control more distal melanophores. 4. 4. Behavior of the transmitter was studied by changing various parameters of the stimulating pulses. The results are discussed in relation to the possible mode of innervation of melanophores. © 1969.