Author/Editor | Arsov, Zoran; Zorec, Robert | |
Title | Alpha-melanocyte stimulating hormone densensitizes the responsiveness of carbon-fibres within seconds | |
Type | članek | |
Source | Pflugers Arch | |
Vol. and No. | Letnik 440, št. 5 Suppl | |
Publication year | 2000 | |
Volume | str. R155-6 | |
Language | eng | |
Abstract | We monitored electrooxidation of noradrenaline and alpha-melanocyte stimulating hormone (alpha-MSH) at a carbon-fibre microelectrode (CFME). The solution of noradrenaline (1 mM) or alpha-MSH (1 mM) was applied by a pressure pulse (2 s) from a micropipette to a voltageclamped (850 mV) CPME immersed into bathing solution of an inverted microscope chamber. The distance between the CFME and micropipette was 2 to 12 micro m. The maximal currents recorded for these two agents were 8.0 +- 0.5 pA (N9) and 3.0 +- 1.1 pA (N = 9), respectively. Pressure application of cotrol solution did not affect the measured current. The noradrenaline-evoked anodic current was characterized by a monotonic increase that attained the maximum at the end of the pressure pulse. In contrast, the time-course of the alpha-MSH-evoked current was biphasic. The maximum amplitude of this current was attained in 0.59 +- 0.15 s (N = 9) and than it declined with a time constant of 7.5 +- 4.0 s (N = 9) until the pressure pulse was terminated. We explain this phenomenon to be due to an interaction between the peptide oxidation products and the CFME which results in its desensitization. | |
Descriptors | MSH NOREPINEPHRINE MICROELECTRODES PATCH-CLAMP TECHNIQUES |