In the teleost retina, the photoreceptors and retinal pigment epithelium (RPE) undergo extensive movements (called retinomotor movements) in response to changes in light conditions and to an endogenous circadian rhythm. Photoreceptor movements serve to reposition the light-receptive outer segments and are effected by changes in inner segment length. Melanin granule movements within the RPE cells provide a movable melanin screen for rod outer segments. In the dark (night), cones elongate, rods contract, and pigment granules aggregate to the base of the RPE cell; in the light (day), these movements are reversed. We report here that treatments that elevate cytoplasmic cyclic adenosine 3',5'-monophosphate (cAMP) provoke retinomotor movements characteristic of nighttime dark adaptation, even in bright light at midday. To illustrate this response, we present a quantitative description of the effects of cyclic nucleotides on cone length in the green sunfish, Lepomis cyanellus. Cone elongation is induced when light-adapted retinas are exposed to exogenous cAMP analogues accompanied by phosphodiesterase (PDE) inhibitors (either by intraocular injection or in retinal organ culture). Cone movements is not affected by cyclic GMP analogies. Dose-response studies indicate that the extent, but not the rate, of cone elongation is proportional to the concentration of exogenous cAMP and analogue presented. As has been reported for other species, we find that levels of cAMP are significantly higher in dark- than in light-adapted green sunfish retinas. On the basis of these observations, we suggest that cAMP plays a role in the light and circadian regulation of teleost cone length.
Skip Nav Destination
Article navigation
1 May 1982
Article|
May 01 1982
Induction of dark-adaptive retinomotor movement (cell elongation) in teleost retinal cones by cyclic adenosine 3','5-monophosphate.
B Burnside
M Evans
R T Fletcher
G J Chader
Online ISSN: 1540-7748
Print ISSN: 0022-1295
J Gen Physiol (1982) 79 (5): 759–774.
Citation
B Burnside, M Evans, R T Fletcher, G J Chader; Induction of dark-adaptive retinomotor movement (cell elongation) in teleost retinal cones by cyclic adenosine 3','5-monophosphate.. J Gen Physiol 1 May 1982; 79 (5): 759–774. doi: https://doi.org/10.1085/jgp.79.5.759
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionSuggested Content
Circadian rhythms in the green sunfish retina.
J Gen Physiol (May,1987)
Effects of extracellular Ca++, K+, and Na+ on cone and retinal pigment epithelium retinomotor movements in isolated teleost retinas.
J Gen Physiol (April,1984)
Visual responses in teleosts. Electroretinograms, eye movements, and circadian rhythms.
J Gen Physiol (July,1992)
Email alerts
Advertisement