Light stimulates the rapid formation of inositol trisphosphate in squid retinas

Szuts, Ete Z.; Wood, S F; Reid, Michael S.; Fein, Alan M.

doi:10.1042/bj2400929

Cited by 75 publications

(33 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Results similar to those presented in the figure were obtained in 11 different flies in which 4-7 cells were examined in each fly.…”

Section: Resultssupporting

confidence: 76%

“…Furthermore, the identification ofthe second messenger for invertebrate phototransduction is still under dispute as inositol trisphosphate (InsP3) (7,8) and cGMP (9) have been found to excite the Limulus ventral photoreceptors. Biochemical studies revealed a light-dependent increase in cGMP in squid retina (9,10), whereas a light-induced increase in InsP3 has been reported in both Limulus photoreceptors (8) and in squid retina (11). In none of these systems, however, has inositol phospholipid hydrolysis been studied in membrane preparations nor has the role of a G protein been analyzed.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Coupling of photoexcited rhodopsin to inositol phospholipid hydrolysis in fly photoreceptors.

Devary

Heichal

Blumenfeld

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

159

111

View full text Add to dashboard Cite

ABSTRACTformed is inositol trisphosphate, and that this product is rapidly hydrolyzed by a specific phosphomonoesterase. Introduction of inositol trisphosphate to the intact photoreceptor cell mimics the effect of light, and bisphosphoglycerate, which inhibits inositol trisphosphate hydrolysis, enhances the effects of inositol trisphosphate and of dim light. The interaction of photoexcited rhodopsin with a G protein is thus similar in both vertebrate and invertebrate photoreceptors. These G proteins, however, activate different photoreceptor enzymes: phospholipase C in invertebrates and cGMP phosphodiesterase in vertebrates.

show abstract

“…Results similar to those presented in the figure were obtained in 11 different flies in which 4-7 cells were examined in each fly.…”

Section: Resultssupporting

confidence: 76%

mentioning

confidence: 99%

Coupling of photoexcited rhodopsin to inositol phospholipid hydrolysis in fly photoreceptors.

Devary

Heichal

Blumenfeld

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

159

111

View full text Add to dashboard Cite

show abstract

“…InsP3 is produced in invertebrate photoreceptors by light Szuts et al 1986;Devary et al 1987;Brown et al 1987). Our observation that the latency of the depolarization and calcium-release induced by InsP~ is similar to, or less than, that induced by light indicates that InsP3 is sufficiently rapid in its action to contribute possibly to the light-induced depolarization.…”

Section: Discussionmentioning

confidence: 71%

The latency of the response of Limulus photoreceptors to inositol trisphosphate lacks the calcium-sensitivity of that to light

Payne

Flores

1992

J Comp Physiol A

View full text Add to dashboard Cite

The latent period before depolarization of Limulus ventral photoreceptors by light flashes was compared with that following brief, intracellular, pressure-injection of d-myo-inositol 1,4,5 trisphosphate. At temperatures between 18 degrees C and 22 degrees C and with an extracellular calcium concentration of 10 mM, the responses of 4 cells to light and to injections of 100 microM inositol trisphosphate displayed average latencies of 71 and 56 ms, respectively. The latencies of responses to InsP3 included an estimated 20 ms dead-time inherent in the injection method. Reducing the temperature lengthened the latency of the response to light (Q10 approximately 3.2 between 7 and 22 degrees C) more than that to inositol trisphosphate (Q10 approximately 2.3). Bathing the photoreceptors in seawater containing no added calcium and 1 mM of the calcium chelator EGTA greatly increased the latency of the light response at all temperatures, but did not increase the latency of the response to inositol trisphosphate. We conclude that the response to inositol trisphosphate lacks the calcium- and temperature-sensitive latent period which characterizes the response to light. If inositol trisphosphate acts, via the release of stored calcium, to stimulate an intermediate in the visual cascade, then that intermediate would appear to be downstream from the latency-generating mechanism.

show abstract

“…Initial support for the messenger role of IP3 came from studies which showed that injections of IP3 into Limulus ventral photoreceptors produce transient membrane depolarizations which result from underlying membrane currents having the same reversal potentials as those produced by brief flashes of light (Brown et al, 1984b;Fein et al, 1984). THE JOURNAL OF GENERAL PHYSIOLOGY • VOLUME 97 -1991 Further support comes from biochemical studies demonstrating light-induced increases in IP3 or its degradation product, inositol 4,5-bisphosphate (IPz) in Limulus ventral photoreceptors (Brown et al, 1984b), squid retinas (Szuts et al, 1986;Brown et al, 1987;Wood et al, 1989) and fly photoreceptors (Devary et al, 1987;Inoue et al, 1988). Finally, the Drosophila no receptor potential (norpA) mutant has been shown to have abnormally low levels of phospholipase C (PL-C) activity, the enzyme that cleaves PIP z to form IPs (Inoue et al, 1985;Yoshioka and Inoue, 1987), and the norpA protein (defective in the norpA mutant) has extensive sequence similarity to a known PL-C (Bloomquist et al, 1988).…”

Section: Introductionmentioning

confidence: 80%

The role of the inositol phosphate cascade in visual excitation of invertebrate microvillar photoreceptors.

Frank

Fein

1991

The Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

The identity of the transmitter(s) involved in visual transduction in invertebrate microvillar photoreceptors remains unresolved. In this study, the role of inositol 1,4,5-trisphosphate (IPs) was examined in Limulus ventral photoreceptors by studying the effects on the light response of heparin and neomycin, agents that inhibit the production or action of IP 3. Both heparin and neomycin reduce responses to brief flashes of light and the transient component of responses to steps of light, and also inhibit IPa-induced calcium release, indicating that IP s plays a direct role in invertebrate visual excitation. The effects of BAPTA, a calcium buffer, were also examined and shown to be consistent with a role for IPa-mediated calcium release in visual excitation. However, all three agents fail to block the plateau component of the response to a step of light, indicating that a single pathway involving IP~ and calcium cannot solely be responsible for visual excitation in invertebrates. We suggest that the inositol phosphate cascade and a second parallel process that is not dependent on IP 3 are involved in the production of the light response.

show abstract

Light stimulates the rapid formation of inositol trisphosphate in squid retinas

Cited by 75 publications

References 21 publications

Coupling of photoexcited rhodopsin to inositol phospholipid hydrolysis in fly photoreceptors.

Coupling of photoexcited rhodopsin to inositol phospholipid hydrolysis in fly photoreceptors.

The latency of the response of Limulus photoreceptors to inositol trisphosphate lacks the calcium-sensitivity of that to light

The role of the inositol phosphate cascade in visual excitation of invertebrate microvillar photoreceptors.

Contact Info

Product

Resources

About