. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. .2 04- 5 02 Log 1 =-3 Log I = -4 D 20-, Ringer !• Picrotoxin H Picrotoxin Control I -5 Log I Ringer 200nM Picrotoxin 100 nM Histidine +200 (iM Pic;. Figure 1. The c/iir chelntor histidine increases sensitivity of the skate electroretinogram (ERG) b-wave response. (A) ERG responses recorded from a dark-adapted skate eyeciip preparation in response to a I-x flash of white light at an intensity of Log I = -3 (Unattenuated beam intensity. Log 1 = 0, was 260 nW/cnr). The amplitude of the b-wave ("b". upper
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. .2 04- 5 02 Log 1 =-3 Log I = -4 D 20-, Ringer !• Picrotoxin H Picrotoxin Control I -5 Log I Ringer 200nM Picrotoxin 100 nM Histidine +200 (iM Pic;. Figure 1. The c/iir chelntor histidine increases sensitivity of the skate electroretinogram (ERG) b-wave response. (A) ERG responses recorded from a dark-adapted skate eyeciip preparation in response to a I-x flash of white light at an intensity of Log I = -3 (Unattenuated beam intensity. Log 1 = 0, was 260 nW/cnr). The amplitude of the b-wave ("b". upper trace) of the ERG recorded from a dark-adapted skate eyecup preparation increased when 100 histidine (in the presence of 200 picrotoxin to block :inc-sensitive GABA receptors} was added to the superfusate. A small increase in the a-wtive < "a ". upper trace) was sometimes seen as well. IB) Intensity-response data from one e\ecup preparation in Ringer. 200 juM picrotoxin. and 100 histidine plus 200 picrotoxin. (C) Nonna/i-ed data at Log I = -4 from 5 preparations. (D) Intensity-response data, averaged and plotted (mean ± SEM). with curves representing the best fit to the Naka-Rushton equation fur each condition. The Log I of the half-amplitude intensity (a) of these curves determined in Ringer. 200 fjM picrotoxin, and in 100 /xM histidine plus 200 picrotoxin were —, — and — respectiveh: Thus, in addition to a 50% increase in V,,,,M. a for the histidine intensity-response curve irm shifted ' lot; units to the left, representing a 6-fold increase in sensitivity in the presence of histidine. volved. the evidence that removal of extracellular zinc by chelation alters the sensitivity of the physiological response to light in an all-rod retina suggests that zinc may be playing an important role as a neuromodulator of rod afferent pathways in the vertebrate retina. Supported by PSC/CUNY grant 65711-0034. Literature Cited I Wu,
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
