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