title: Electrophysiological effects of tachykinin analogues on ganglion cell activity in cyprinid fish retina.
abstract: Electrical spike activity of ganglion cells has been recorded extracellularly in the teleost (roach) retina, and effects of a variety of tachykinins studied at a working concentration of 1 microM. Application of substance P mostly caused a slow and prolonged increase in background activity. In contrast, the response to carbachol was very brisk and short-lasting. Substance P and physalaemin predominantly induced an enhancement of 'On' and 'Off' components of light-evoked responses, whilst eledoisin and neurokinin A were mostly inhibitory. All effects were independent of chromatic and spatial aspects of the responses. Interestingly, in the presence of a tachykinin antagonist, 'Spantide' [D-Arg1,D-Pro2, D-Trp7.9, Leu11]SP, the profile of the effect of substance P reversed, inhibitory actions becoming much more common. Taken together, the results suggest that a tachykinin system utilising two subtypes of the receptor may be active in the roach retina and these may be involved in differential control of visual sensitivity.
authors.affiliation: Department of Biology, Imperial College of Science, London, UK.
authors.forename: J E
authors.initials: JE
authors.lastname: Downing
authors.forename: M B
authors.initials: MB
authors.lastname: Djamgoź
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000528:radiation effects; D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D004600:Eledoisin / Q000494:pharmacology; D015288:Neurokinin A / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D010803:Physalaemin / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology; D018039:Receptors, Tachykinin; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D013045:Species Specificity; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology; D015320:Tachykinins / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D010446:Peptide Fragments; D011480:Protease Inhibitors; D017981:Receptors, Neurotransmitter; D018039:Receptors, Tachykinin; D015320:Tachykinins; D010803:Physalaemin; D013373:Substance P; D004600:Eledoisin; C032720:substance P (5-11), pGlu(5)-MePhe(8)-MeGly(9)-; D015288:Neurokinin A; C042867:spantide; D011761:Pyrrolidonecarboxylic Acid