Effects of dopamine receptor blockade on the intensity-response function of electroretinographic b- and d-waves in light-adapted eyes

Popova, E.

doi:10.1007/s00702-013-1103-0

Cited by 5 publications

(7 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2A, B). This amplitude decline was probably produced by the adaptational effect of the test stimulation itself and it was also seen in other ERG recordings in dark adapted frog eyecups (Popova and Kupenova, 2016;Kupenova et al, 2017). Because the d-wave amplitude diminished to a greater extent than that of the b-wave ( Fig.…”

Section: Intensity-response Function Of Control Experimentssupporting

confidence: 64%

Effects of HCN channel blockade on the intensity-response function of electroretinographic ON and OFF responses in dark adapted frogs

Popova¹,

Kupenova²

2020

Acta Neurobiologiae Experimentalis

View full text Add to dashboard Cite

Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are well expressed in the vertebrate retina. Their role in formation of electroretinographic (ERG) responses to stimulus onset (b-wave) and stimulus offset (d-wave) are largely unknown. In this study we investigated the effects of pharmacological blockade of HCN channels (with ZD7288 or ivabradine) on the ERG band d-waves in dark adapted frog eyecup preparations. Initially, the dose-response relationship of ZD7288 effects on the band d-waves was investigated. Afterwards, the effects of 75 μM ZD7288 on the stimulus-response function of the ERG band d-waves were explored over a wide intensity range (10 log units). Finally, the effects of 30 μM ivabradine on the same function were studied. Perfusion with 75 μM ZD7288 did not change the absolute and relative sensitivity of the ERG ON and OFF responses. It caused an enhancement of the d-wave amplitude at all suprathreshold stimulus intensities, while the b-wave amplitude was slightly enhanced only in the range of higher intensities. As a result of the greater blocker effect on the OFF response amplitude, the b/d amplitude ratio was significantly decreased over the whole intensity range. ZD7288 caused a prolongation of the b-wave half-width duration, but a shortening of the d-wave half-width duration at higher intensities. Similar results were obtained when 30 μM ivabradine was used for HCN channel blockade. Our results clearly demonstrate that the blockade of retinal HCN channels changes the balance between the ON and OFF responses in the distal frog retina. This ON/OFF imbalance may be one of the causes for visual disturbances reported in ivabradine treated patients.

show abstract

Section: Intensity-response Function Of Control Experimentssupporting

confidence: 64%

Effects of HCN channel blockade on the intensity-response function of electroretinographic ON and OFF responses in dark adapted frogs

Popova¹,

Kupenova²

2020

Acta Neurobiologiae Experimentalis

View full text Add to dashboard Cite

show abstract

“…The absolute and relative sensitivities of the responses were not significantly changed during the blocker application (Table I). These results indicate that 40 μM sulpiride had no significant influence on the V -log I function of the light-adapted turtle ERG, which contrasted with its suppressive action of the amplitude of the light-adapted frog ERG (Popova 2014b). We did not find any significant effects of 40 μM sulpiride on the time characteristics of the turtle ERG waves as well.…”

Section: Effects Of 40 μM Sulpiride On the Intensity-response Function Of Turtle Ergmentioning

confidence: 73%

“…The eyecup preparations were placed in a chamber where they were continuously superfused with Ringer solution (NaCl 110 mM, KCl 2.6 mM, NaHCO 3 10 mM, CaCl 2 2 mM, MgCl 2 2 mM, Glucose 2 mM; HCl 0.5 mM to adjust pH to 7.8) at a rate of 1.6 -1.8 ml/min, temperature 18 -20 0 C and supplied with moistened O 2 (for details see Kupenova et al 2010, Popova 2014b). The D2-class receptors were blocked by sulpiride (Santa Cruz Biotechnology, Inc., Dallas, TX).…”

Section: Subjects and Drug Applicationmentioning

confidence: 99%

“…These concentrations cover the higher range of concentrations used in ERG experiments with lower vertebrate species (tiger salamander-10 μM, Perry and George 2007;goldfish-10 μM, Mora-Ferrer andBehrend 2004, 200 μM, Kim andJung 2012). In frogs, only the highest concentration (240 μM) was tested and the results were compared with effects obtained from the lowest concentration tested in our previous study (Popova 2014b). The latter was done in order to exclude a nonspecific effect of application for this very high concentration.…”

Section: Experimental Procedures and Groupsmentioning

confidence: 99%

“…As the effect of sulpiride on the turtle ERG wave amplitude was opposite to the effect obtained in the frog ERG, and because it was expressed only at the highest concentration of the blocker, a question arose regarding its specificity. To test this possibility, we studied the effects of 240 μM sulpiride on the intensity-response function of the frog ERG waves and compared them to the effects of 40 μM sulpiride obtained in our previous study (Popova 2014b). In the control experiments for this group (n=6) no significant differences were observed between the first and second V -log I function of the b-and d-waves within the same eyecup (two-way repeated measures ANOVA, p>0.05) (Fig.…”

Section: Effects Of 240 μμ Sulpiride On the Intensity-response Function Of Frog Ergmentioning

confidence: 99%

See 2 more Smart Citations

Dopamine D2 receptor blockade differentially affects the light-adapted turtle and frog electroretinogram

Popova¹,

Kupenova²

2018

Acta Neurobiologiae Experimentalis

View full text Add to dashboard Cite

The effects of dopamine D2-class receptor blockade by sulpiride on the electroretinographic (ERG) b-wave (ON response) and d-wave (OFF response) were investigated in light-adapted turtle (Trachemys scripta elegans) and frog (Rana ridibunda) eyecups. For turtle ERG, sulpiride (240 μM) produced an amplitude increase of the band d-waves, while the 40 μM and 120 μM of sulpiride were ineffective. Alternatively, for frog ERG, a well-developed and dose-dependent band d-wave amplitude decrease was obtained with 40 μM and 240 μM sulpiride. In both species, 240 μM sulpiride significantly affected the maximal voltage range of the ERG responses without altering their relative sensitivity (determined by the semi-saturation point). The absolute sensitivity of the ON and OFF responses (evaluated by threshold estimation) was not significantly altered for turtle ERG, but it was decreased for frog ERG. The time characteristics of the ERG responses were unchanged in both species. Our results show important differences between dopamine D2-class receptor-mediated pathways in turtle and frog retina (revealed by ERG).

show abstract

Role of dopamine in distal retina

Popova

2014

J Comp Physiol A

View full text Add to dashboard Cite

Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences.

show abstract

Effects of dopamine receptor blockade on the intensity-response function of electroretinographic b- and d-waves in light-adapted eyes

Cited by 5 publications

References 58 publications

Effects of HCN channel blockade on the intensity-response function of electroretinographic ON and OFF responses in dark adapted frogs

Effects of HCN channel blockade on the intensity-response function of electroretinographic ON and OFF responses in dark adapted frogs

Dopamine D2 receptor blockade differentially affects the light-adapted turtle and frog electroretinogram

Role of dopamine in distal retina

Contact Info

Product

Resources

About