scholarly journals Cone ERG Changes During Light Adaptation in Two All-Cone Mutant Mice: Implications for Rod-Cone Pathway Interactions

2019 ◽  
Vol 60 (10) ◽  
pp. 3680
Author(s):  
Ronald A. Bush ◽  
Atsuhiro Tanikawa ◽  
Yong Zeng ◽  
Paul A. Sieving
Keyword(s):  
Light Adaptation ◽  
Mutant Mice ◽  
Cone Pathway

The d-wave of the rod electroretinogram of rat originates in the cone pathway

1999 ◽  
Vol 16 (1) ◽  
pp. 91-105 ◽  
Author(s):  
FRANK NAARENDORP ◽  
GEORGE E. WILLIAMS
Keyword(s):  
Time Course ◽  
Light Adaptation ◽  
Light Response ◽  
Receptor Potential ◽  
Bipolar Cells ◽  
Positive Component ◽  
Long Duration ◽  
Cone Pathway ◽  
Rod Electroretinogram ◽  
Stimulus Offset

We studied the off-response of the rat ERG evoked with long duration, mesopic stimuli during light and dark adaptation, and after intravitreal injection of aspartate and (±)-cis-piperidine-2,3-dicarboxilic acid (PDA). At stimulus offset, the dark-adapted ERG always showed a rapid negative deflection followed by a positive deflection after which the potential returned to baseline. When the stimulus was turned off in the presence of a background of scotopic intensity, the positive deflection consisted of two components. One component was relatively small, fast, and insensitive to rod light adaptation. It resembled the d-wave of the rod ERG. The other component was slow and its amplitude grew with rod light adaptation. In the presence of aspartate, the fast-positive component was absent from the ERG while the remaining positive-going decay of the receptor potential had a time course similar to that of the slow-positive component in the untreated eye. Scotopically matched red and blue stimuli of mesopic intensity elicited equal ERG responses from the dark-adapted eye, including the two positive components in the off-response. These stimuli were also used to assess changes in the ERG off-response during recovery from a strong bleach. Even though the cone contribution to the rat ERG is very small, the presence of a small positive-going component in the off-response following an intense bleach suggested that this response originated from the cone pathway. PDA which suppresses the light response of hyperpolarizing bipolar cells and horizontal cells selectively eliminated the fast-positive component from the ERG. The findings of this study are inconsistent with the idea that the d-wave reflects the decay of the rod receptor potential. They support the possibility that signals from rods cross rod–cone gap junctions at mesopic light intensities, and drive second-order neurons in the cone pathway.

Connexin 36 in bovine retina: Lack of phosphorylation but evidence for association with phosphorylated proteins

2003 ◽  
Vol 20 (4) ◽  
pp. 385-395 ◽  
Author(s):  
ARI SITARAMAYYA ◽  
JOHN W. CRABB ◽  
DIANE F. MATESIC ◽  
ALEXANDER MARGULIS ◽  
VINITA SINGH ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Cyclic Nucleotide ◽  
Visual Information ◽  
Information Transfer ◽  
Light Adaptation ◽  
Connexin 36 ◽  
Phosphorylated Proteins ◽  
Bovine Retina ◽  
Cone Pathway

In vertebrate retina interneuronal communication through gap junctions is involved in light adaptation and in the transfer of visual information from the rod pathway to the cone pathway. Reports over the last two decades have indicated that these gap junctions are regulated by cyclic nucleotide-dependent protein kinases suggesting that the gap junction proteins, connexins, are phosphorylated. Though all the connexins involved in light adaptation and information transfer from rod to cone pathway are not yet known, connexin 36 has been shown to be definitively involved in the latter process. We have therefore attempted to investigate the cyclic nucleotide-dependent phosphorylation of this connexin in bovine retina. We found several soluble and membrane proteins in bovine retina whose phosphorylation was regulated by cyclic nucleotides. However, no protein of about 36 kDa with cyclic nucleotide-regulated phosphorylation was found in gap junction-enriched membrane preparations. A 36-kDa phosphorylated protein was found in gap junction-enriched membranes phosphorylated in the presence of calcium. However, this protein was not immunoprecipitated by anti-connexin 36 antibodies indicating that it was not connexin 36 in spite of its similarity in molecular weight. Immunoprecipitation did reveal phosphorylated proteins coimmunoprecipitated with connexin 36. Two of these proteins were identified as beta and alpha tubulin subunits. Though cyclic GMP and calcium did not greatly influence the association of these proteins with connexin 36, the results suggest the possibility of connexin 36 associating with other proteins. Together, these observations indicate that interneuronal communication at gap junctions made by connexin 36 may not be regulated by direct phosphorylation of connexin 36, but possibly by phosphorylation of associated proteins.

New insights into heparan sulphate biosynthesis from the study of mutant mice

2002 ◽  
Vol 69 ◽  
pp. 47-57 ◽  
Author(s):  
Catherine L. R. Merry ◽  
John T. Gallagher
Keyword(s):  
Growth Factors ◽  
Biosynthetic Pathway ◽  
Heparan Sulphate ◽  
Mutant Mice ◽  
Gene Products ◽  
Multiple Gene ◽  
Adhesion Proteins ◽  
Ligand Interactions

Heparan sulphate (HS) is an essential co-receptor for a number of growth factors, morphogens and adhesion proteins. The biosynthetic modifications involved in the generation of a mature HS chain may determine the strength and outcome of HS–ligand interactions. These modifications are catalysed by a complex family of enzymes, some of which occur as multiple gene products. Various mutant mice have now been generated, which lack the function of isolated components of the HS biosynthetic pathway. In this discussion, we outline the key findings of these studies, and use them to put into context our own work concerning the structure of the HS generated by the Hs2st-/- mice.

Author response for "Protection from EAE in DOCK8 mutant mice occurs despite increased Th17 cell frequencies in the periphery"

2018 ◽  
Author(s):  
Alicia S. Wilson ◽  
Hsei Di Law ◽  
Christiane B. Knobbe‐Thomsen ◽  
Conor J. Kearney ◽  
Jane Oliaro ◽  
...  
Keyword(s):  
Th17 Cell ◽  
Mutant Mice ◽  
Author Response
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