title: Effects of cyclic nucleotides and calcium on transduction and encoding processes in frog muscle spindle.
abstract: In decapsulated muscle spindles, application of dibutyryl cyclic AMP (d-cAMP, 0.1-10 mM) and forskolin (10-100 microM) increased the rate of spontaneous discharges and decreased the responsiveness to stretch. Addition of 2-5 mM CaCl2 or 0.5-2 mM BaCl2 to the above drugs prevented the deterioration of the responsiveness to stretch and the increase in the rate of spontaneous discharges. Similar changes in the afferent discharges were observed with application of isobutylmethyl-xanthine (IBMX, 0.5-2 mM) or carbonyl cyanide chlorophenylhydrazone (CCCP, 1-10 microM). Application of 0.1-1 mM quercetin resulted in a prolonged increase in the discharge rate, lasting 15-20 s after the release of stretch. These results suggest that cAMP is involved in the regulation of the sensory processes through a modification of intracellular calcium activity.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001464:Barium / Q000494:pharmacology; D017609:Barium Compounds; D003994:Bucladesine / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002712:Chlorides; D005576:Colforsin / Q000494:pharmacology; D066298:In Vitro Techniques; D009132:Muscles / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D011794:Quercetin / Q000494:pharmacology; D011892:Rana catesbeiana
chemical_list: D017609:Barium Compounds; D002712:Chlorides; C024986:barium chloride; D005576:Colforsin; D001464:Barium; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D003994:Bucladesine; D011794:Quercetin; D002122:Calcium Chloride; D015056:1-Methyl-3-isobutylxanthine