COLCHICINE, CYTOCHALASIN B, AND PIGMENT MOVEMENTS IN OVARIAN AND INTEGUMENTARY ERYTHROPHORES OF THE PRAWN, PALAEMONETES VULGARIS

1. The effects of colchicine and cytochalasin B on pigment migration in integumentary erythrophores of the prawn, Palaemonetes vulgaris, were determined.2. Colchicine in a concentration of 25 mM inhibited responses to both the red pigment-concentrating and red pigment-dispersing hormones by the integumentary erythrophores. Colchicine at a concentration of 5 mM did not inhibit the responses of these chromatophores to these hormones.3. Cytochalasin B (10 µg/ml) also inhibited both centrifugal and centripetal migrations of the pigment granules in these integumentary enythrophores.4. Colchicine in a 25 mM solution almost completely inhibited the response to red pigment-concentrating hormone in ovarian erythrophores whereas 1 mM colchicine produced only a slight inhibition of this response.5. The integumentary erythrophores of Palaemonetes vulgaris are the first chromatophores that have been observed in any animal where both pigment dispersion and aggregation are inhibited by either colchicine or cytochalasin B.6. These results are discussed in relation to previously published data from this and other laboratories.