. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 204 REPORTS FROM THE MBL GENERAL SCIENTIFIC MEETINGS Ringer M :•,(.] mi in (ImM) Ringer. Ringer Cimetidine (ImM) Cimetidine (ImM) Figure 1. The action of histamine and cimetidine on eccentric cells of the Limulus lateral eye. (A} Eighty minutes of perfusion with 1 mM histamine reduced both the spontaneous and light driven response of the eccentric cell (57 mV resting potential). Washout u-ith modified Limulus Ringer reversed the effect of histamine. The amplitude of the largest spontaneously evoked action potential was 45 mV
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 204 REPORTS FROM THE MBL GENERAL SCIENTIFIC MEETINGS Ringer M :•,(.] mi in (ImM) Ringer. Ringer Cimetidine (ImM) Cimetidine (ImM) Figure 1. The action of histamine and cimetidine on eccentric cells of the Limulus lateral eye. (A} Eighty minutes of perfusion with 1 mM histamine reduced both the spontaneous and light driven response of the eccentric cell (57 mV resting potential). Washout u-ith modified Limulus Ringer reversed the effect of histamine. The amplitude of the largest spontaneously evoked action potential was 45 mV. but appears in these traces as 18 inV because of the low puss characteristics of the Gould Brush recorder. Note that the intracellular recordings contain action potentials of different amplitudes. The smaller one is generated bv a second eccentric cell in the same ommaridiiini and is detectable became of partial coupling among ommatid/ul cells. The existence of multiple eccentric cells in single ommatidia is not uncommon and can be as high as 20% (R. Barlow, unpiib. ohs.). (B) Twenty minutes of perfusion with I mM Cimetidine reduced the action of lateral inhibition and forty minutes of perfusion abolished it. Fortv-fivc minutes of Ringer washout partially reversed the Cimetidine effect (data not shown). Artifacts caused by antidromic shock delivered to the optic nen'e trunk are detect- able in the middle of the first trace. The amplitude of the spontaneously evoked action potential in the second trace was 65 mV, but was attenu- ated to 24 mV by the pen recorder. A/I traces are 18 s in duration. with modified Limulus Ringer. The cell fired large (45 mV) action potentials in response to dim background illumination ( - impulses/s) before the light flash. A second eccentric cell located in the same ommatidium generated much smaller action potentials (— mV) with the same firing rate (see legend). While perfusing the slice with modified Limulus Ringer (first trace), the
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
