Dimethyl sulfoxide elevates intracellular Ca2+and mimics effects of increased light intensity in a photoreceptor

✍ Scribed by H. Mack Brown; Bo Rydqvist

• Book ID: 104746751
• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 443 KB
• Volume: 415
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00373615

✦ Synopsis

A 1% (v/v) solution ofdimethyl sulfoxide (DMSO) added to the saline bath of isolated Balanus eburneus photoreceptors increased receptor potential amplitude by 40-50% and shortened time to peak amplitude and latency by 20-25%. The light-sensitive membrane current of voltage-clamped cells was increased systematically as DMSO concentration was increased from 1% to 10%. The null potential of the light sensitive current was unaffected by DMSO with short pulses of light, indicating that DMSO has no direct effect on ion selectivity of the light-sensitive channel. Absorbance changes of cell injected with the calcium indicator arsenazo III show that DMSO elevates intracellular Ca 2+ (Cai). Current-voltage relations in darkness reveal that DMSO induces a small sustained inward current (~ 5 hA) which has a null potential similar to the lightinduced current. DMSO may activate the light-sensitive conductance via the increase in Cal. However, the altered kinetics and increased amplitude of the receptor current are opposite to the desensitizing effects normally observed with increased Cai.