Abstract
1. 1. Melanophores of Papiliochromis ramirezi aggregate their melanosomes in the presence of catecholamines. 2. 2. Their order of potency are: at 10 −4 M, norepinephrine > isoproterenol = epinephrine; at 10 −6 and 10 −8 M, norepinephrine = isoproterenol > epinephrine. 3. 3. These effects are antagonized not only by phentolamine but also by propranolol. 4. 4. The catecholamines are unable to induce pigment dispersion. 5. 5. Melanosome dispersion is obtained with cholinergic drugs and the order of potency is nicotine > acetylcholine = pilocarpine. 6. 6. Their effects are inhibited by atropine and also by d-tubocurarine and potentiated by physostigmine. 7. 7. The evidences suggest the presence of undifferentiated adrenoceptors, related to the melanosome aggregation and undifferentiated cholinoceptors related to the melanosome dispersion.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Comparative Biochemistry and Physiology. Part C, Comparative Pharmacology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
