The fiber outgrowth induced by ACh, dibutyryl cyclic AMP and dibutyryl cyclic GMP in explanted chick embryonic dorsal root ganglia differed distinctly from that be nerve growth factor (NGF) and submandibular gland extract of adult male mice. Ginsenoside Rb1 potentiated the effects of NGF and submandibular extract at concentrations of 3 and 30 muM, but did not potentiate the effects of ACh, dibu...

Evidence is available to suggest that Ca2+-calmodulin and cyclic nucleotides are involved in the regulation of ion transport in rabbit ileum. Since both Ca2+-calmodulin and cyclic nucleotides exert many of their effects by phosphorylation, the effects of Ca2+-calmodulin and cyclic nucleotides on phosphorylation of purified microvillus membrane from rabbit ileal mucosa were evaluated. Ca2+-calmo...

An assay for measuring 3’,5’-cyclic nucleotide phosphodiesterase activity over a wide range of substrate concentrations has been described. The ratio of cyclic adenosine 3’,5’monophosphate (cyclic AMP) to cyclic guanosine 3’,5’monophosphate (cyclic GMP) hydrolysis varied several fold among crude subcellular fractions from bovine and rat heart when measured at micromolar but not millimolar subst...

Earlier studies have shown that enzyme preparations from a number of tissues are capable of forming small amounts of adenosine 3’) 5’-phosphate (cyclic 3’) 5’-AMP) from adenosine triphosphate (l-3). This nucleotide has been found to have important biological properties, which recently have been reviewed in detail (4, 5). In Paper I of this series attempts to fractionate or to simplify enzyme pr...

In a previous study, we demonstrated that angiotensin II (AngII) inhibited voltage-dependent calcium channels (VDCCs) currents (ICa) in hamster submandibular ganglion (SMG) neurons. In sinoatrial node cells, it has been reported that AngII inhibits ICa by suppressing cyclic AMP production. In this study, to investigate the possible involvement of a cyclic AMP-cyclic AMP dependent protein kinase...

The possibility that an alteration of the vasopressin-dependent cyclic AMP system plays a pathogenic role in the urinary concentrating defect in K+ depletion was investigated in the rat. The antidiuretic response to vasopressin was significantly less in K+-depleted rats. In these K+-depleted rats, the increase in urinary cyclic AMP excretion in response to vasopressin was also significantly les...

Three substances believed to be neurohormones in the lobster--serotonin, octopamine, and proctolin--can modulate the physiology of the dactyl opener muscle of the lobster walking leg. All three act directly on muscle fibers to cause long-lasting contractures. In addition, serotonin enhances the release of transmitter from the excitatory and inhibitory axons that innervate the muscle. We now rep...

Cyclic AMP metabolism in epididymal adipose tissue of exercise-trained rats was examined to determine if training induced changes in cyclic AMP production or inactivation. Beginning at 7 weeks of age, male rats were physically trained by 12 weeks of treadmill running. Pair-fed control rats remained sedentary in their cages for the duration of the experiment. Tissue levels of cyclic AMP were mea...

An increase in the cyclic AMP of nerve terminals has been proposed as intermediary in neurotransmitter release and synthesis (Wooten et al., 1973; Roth et al., 1975). However, de Belleroche et al. (1 974) were unable to increase the cyclic AMP content of synaptosome preparations after their isolation from rat neocortex, using as stimulating agents electrical pulses, noradrenaline or elevated K+...

We identified signals that affect mRNA levels complementary to a gene that is highly expressed in vegetative Dictyostelium discoideum cells. This gene has been cloned as cDNA in the plasmid pcD-D2. The level of transcripts homologous to pcD-D2 fell dramatically in strain XP55 during the aggregation stage of development when cells differentiate on agar. The level, however, did not fall simply as...