scholarly journals Changes in cyclic AMP and cyclic GMP concentrations during the action of 5-hydroxytryptamine on an insect salivary gland

1980 ◽  
Vol 192 (1) ◽  
pp. 247-255 ◽  
Author(s):  
J P Heslop ◽  
M J Berridge
Keyword(s):  
Salivary Gland ◽  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Time Course ◽  
Phosphodiesterase Inhibitor ◽  
Fluid Secretion ◽  
Fast Response ◽  
Bathing Medium ◽  
Calliphora Erythrocephala

Salivary glands from adult blowflies (Calliphora erythrocephala Meigen) were studied in vitro. The time course of changes in cyclic AMP content of the glands was followed at different concentration of 5-hydroxytryptamine. There was an immediate biphasic rise and fall in cyclic AMP content, following by a slower rise and subsequent gradual decline. The initial rise preceded the onset of fluid secretion by the glands. Rises in cyclic AMP content were inhibited by compound RMI 12330 A (an adenylate cyclase inhibitor) and were halted after about 15-20s if the glands were deprived of Ca2+. Theophylline (a phosphodiesterase inhibitor) abolished the decline phase of the fast response, Losses of cyclic AMP from the glands either to the bathing medium or to the saliva were small and could not account for the rapid fall found. Evidence is presented that cyclic GMP is not involved in the process of initiating secretion in the blowfly salivary gland.

CYCLIC AMP AND CYCLIC GMP ACCUMULATION IN HAMSTER PRE-OVULATORY FOLLICLES STIMULATED WITH LH AND FSH

1978 ◽  
Vol 87 (1) ◽  
pp. 158-163 ◽  
Author(s):  
Anastasia Makris ◽  
Kenneth J. Ryan
Keyword(s):  
Cyclic Amp ◽  
Dose Response ◽  
Cyclic Gmp ◽  
Time Course ◽  
Hormone Action ◽  
Acute Response ◽  
Cyclic Amp Accumulation ◽  
Ovulatory Follicles ◽  
Higher Doses

ABSTRACT Cyclic AMP and cyclic GMP accumulation in hamster pre-ovulatory follicles was determined after in vitro stimulation by LH and FSH. Combined time course and dose response experiments determined that the acute response of the follicles (0–30 min) to LH and FSH was similar with respect to cyclic AMP accumulation. The pattern of cyclic GMP accumulation was, however, distinctly different in LH and FSH stimulated follicles. LH increased follicular cyclic GMP only at the lowest dose (0.005 IU/ml), while higher doses of LH had no effect. In contrast, FSH at all doses stimulated cyclic GMP accumulation. The different cyclic AMP to cyclic relationships generated in the follicles by LH and FSH may be determinants in specificity of hormone action in pre-ovulatory follicles.

Ion and Water Balance in the Ixodid Tick Dermacentor Andersoni

1973 ◽  
Vol 58 (2) ◽  
pp. 549-564
Author(s):  
W. R. KAUFMAN ◽  
J. E. PHILLIPS
Keyword(s):  
Salivary Gland ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Artificial Medium ◽  
Salivary Duct ◽  
Bathing Medium ◽  
Dermacentor Andersoni ◽  
Cl Secretion ◽  
Wide Range

1. The salivary gland of the ixodid tick, Dermacentor andersoni, can be induced to secrete fluid for at least 6 h when bathed in an artificial medium in vitro. 2. Fluid secretion appears to be a consequence of active Cl secretion since (a) it is inhibited by 95% when nitrate and by 100% when acetate replaces Cl in the bathing medium; however, bromide can support secretion as well as Cl, (b) the rates of fluid and Cl secretion are linearly related to the concentration of Cl in the medium; and (c) the S/H ratio for Cl is greater than unity at all concentrations despite a transacinar P.D. of 35 mV (lumen negative). 3. Although (in the presence of Na) a low concentration of K in the bathing medium stimulates the rate of fluid secretion fivefold, higher concentrations of K inhibit fluid secretion. The latter is largely due to a direct effect of K ion and not simply to increased osmotic pressure or reduced Na concentration. Fluid secretion is completely in hibited by 10-6 M ouabain. On the basis of these observations we propose that fluid secretion may be dependent on a Na-K activated ‘pump ATPase’, which is somehow involved in cation secretion. The S/H ratios of Na and K are greater than unity at all medium concentrations. 4. The saliva secreted in vitro is slightly hypo-osmotic to the bathing medium over a wide range of medium concentration (300-920 mOsm/l). We postulate that the primary saliva is iso- or hyper-osmotic to the bathing medium; the final elaborated saliva is probably rendered hypo-osmotic by a process of solute reabsorption somewhere between the acini and the orifice of the main salivary duct.

Antagonistic control of fluid secretion by the Malpighian tubules ofTenebrio molitor: effects of diuretic and antidiuretic peptides and their second messengers

2002 ◽  
Vol 205 (4) ◽  
pp. 493-501 ◽  
Author(s):  
U. I. M. Wiehart ◽  
S. W. Nicolson ◽  
R. A. Eigenheer ◽  
D. A. Schooley
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Second Messengers ◽  
Fluid Secretion ◽  
Tenebrio Molitor ◽  
Inhibitory Effect ◽  
Malpighian Tubules ◽  
Dependent Manner ◽  
Response Curves

SUMMARYFluid secretion by insect Malpighian tubules is controlled by haemolymph-borne factors. The mealworm Tenebrio molitor provides the first known example of antagonistic interactions between endogenous neuropeptides acting on Malpighian tubules. The two corticotropin-releasing-factor (CRF)-related diuretic peptides previously isolated from Tenebrio molitor, Tenmo-DH37 and Tenmo-DH47, were found to stimulate Tenebrio molitor tubules in vitro in a dose-dependent manner with EC50 values of 0.12 nmol l–1 and 26 nmol l–1 respectively. However, no synergistic or additive effect was observed when these two peptides were tested simultaneously. We then investigated antagonism between second messengers: dose–response curves were constructed for stimulation of Tenebrio molitor tubules by cyclic AMP and their inhibition by cyclic GMP. When both cyclic nucleotides were included in the bathing Ringer, the stimulatory effect of cyclic AMP was neutralised by cyclic GMP. Similarly, the stimulatory effect of Tenmo-DH37 was reversed on addition of an antidiuretic peptide (Tenmo-ADF), which was recently isolated from Tenebrio molitor and acts via cyclic GMP. The cardioacceleratory peptide CAP2b, originally isolated from Manduca sexta, also increases intracellular cyclic GMP levels and inhibited fluid secretion by Tenebrio molitor tubules, with an EC50 value of 85 nmol l–1. This inhibitory effect was reversed by Tenmo-DH37. Endogenous diuretic and antidiuretic peptides, effective at low concentrations and acting via antagonistic second messengers, have the potential for fine control of secretion rates in the Malpighian tubules of Tenebrio molitor.

Effect of Cyclic AMP and Cyclic GMP on Thromboplastin (Factor III) Synthesis in Human Monocytes In Vitro

1983 ◽  
Vol 50 (04) ◽  
pp. 804-809 ◽  
Author(s):  
Torstein Lyberg
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Immune Complexes ◽  
Phosphodiesterase Inhibitors ◽  
Inhibitory Effect ◽  
Intracellular Camp ◽  
Human Monocytes ◽  
Purified Protein Derivative ◽  
A 23187

SummaryHuman monocytes in vitro respond to various agents (immune complexes, lectins, endotoxin, the divalent ionophore A 23187, 12-0-tetradecanoyl-phorbol 13-acetate [TPA], purified protein derivative [PPD] of Bacille Calmette-Guerin) with an increased synthesis of the protein component of thromboplastin. The effect of cyclic AMP and cyclic GMP on this response has been studied. Dibutyryl-cyclic AMP, prostaglandin E1 and the phosphodiesterase inhibitors 3-butyl-1-methyl-xanthine (MIX) and rac -4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro 201724), separately and in combination have a pronounced inhibitory effect on the response to immune complexes and PPD, and a moderate effect on the response to endotoxin and lectins. The effect on TPA response and on the response to A 23187 was slight. Dibutyryl-cyclic GMP (1 mM) gave a slight inhibition of the TPA arid IC response, but had essentially no effect on the response to other inducers. The intracellular cAMP level increased when monocytes were incubated with IC, TPA or A 23187 followed by a decrease to basal levels within 1-2 hr, whereas lectin (PHA) and PPD did not induce such changes. The cAMP response to endotoxin varied. Stimulation with IC induced an increase in monocyte cGMP levels, whereas the other stimulants did not cause such changes.

Fluid secretion in the nephron: Relation to renal failure

1976 ◽  
Vol 56 (1) ◽  
pp. 248-258 ◽  
Author(s):  
J. J. Grantham
Keyword(s):  
Fluid Transport ◽  
Fluid Secretion ◽  
Cystic Kidney Disease ◽  
Rabbit Kidney ◽  
Cystic Kidney ◽  
Obstructive Nephropathy ◽  
Bathing Medium ◽  
Pars Recta ◽  
Uremic Syndrome

It had been generally accepted that glomerular filtration and tubular reabsorption were the basic modes of fluid transport in mammalian nephrons. Recently, evidence was obtained to indicate that net fluid secretion may occur in mammalian nephrons as well. In the pars recta portion of proximal tubules of rabbit kidney net fluid secretion was observed in vitro in response to PAH and other aryl acids in the peritubular bathing medium. Net fluid secretion appeared to be coupled to the transcellular transport of aryl acid from bath to lumen. Serum from uremic subjects stimulated net fluid secretion in the pars recta in a manner similar to PAH. The accumulation of high levels of endogenous aryl acids may contribute to the general organ dysfunction that is a part of the uremic syndrome of advanced renal insufficiency. Futhermore, there is evidence to suggest that the fluid-secretion phenomenon in association with aryl acids may significantly affect renal excretion and morphology in slow-flow states, in patients with cystic kidney disease, and in obstructive nephropathy.

Possible role of cyclic GMP in stimulus-secretion coupling by salt gland of the duck

1979 ◽  
Vol 237 (5) ◽  
pp. C200-C204 ◽  
Author(s):  
D. J. Stewart ◽  
J. Sax ◽  
R. Funk ◽  
A. K. Sen
Keyword(s):  
Cyclic Amp ◽  
Guanylate Cyclase ◽  
Cyclic Gmp ◽  
Salt Gland ◽  
Domestic Ducks ◽  
Stimulus Secretion Coupling ◽  
Stimulation Of

Stimulation of salt galnd secretion in domestic ducks in vivo increased the cyclic GMP concentration of the tissue, but had no effect on cyclic AMP levels. Methacholine, which is known to stimulate sodium transport by the glands both in vivo and in vitro, stimulated ouabain-sensitive respiration in salt gland slices. Cyclic GMP stimulated ouabain-sensitive respiration to the same extent as methacholine. Guanylate cyclase stimulators, hydroxylamine and sodium azide, also stimulated ouabain-sensitive respiration. The stimulation of ouabain-sensitive respiration by methacholine was blocked either by atropine or by removal of calcium from the incubation medium. The stimulation of ouabain-sensitive respiration by cyclic GMP still occurred in the absence of calcium. The above observations seem to indicate that cyclic GMP acts as a tertiary link in the process of stimulus-secretion coupling in the tissue.

Reversible effects of phenothiazines on frog gastric stimulation

1984 ◽  
Vol 247 (4) ◽  
pp. G366-G376
Author(s):  
N. Raphael ◽  
E. B. Ekblad ◽  
T. E. Machen
Keyword(s):  
Adenylate Cyclase ◽  
Time Course ◽  
Phosphodiesterase Inhibitor ◽  
Secretory Activity ◽  
Gastric Stimulation ◽  
Camp Content ◽  
Oxyntic Cell ◽  
Camp Generation ◽  
Stimulus Secretion Coupling

The calmodulin inhibitors trifluoperazine (TFP), chlorpromazine (CPZ), and promethazine (PZ) were tested for effects on stimulus-secretion coupling in in vitro bullfrog gastric mucosa. When added to histamine-stimulated tissues, the drugs caused H+ secretion to decrease and transepithelial resistance to increase over a 2-h time course. The potency sequence was TFP (IC50 = 40 microM) greater than CPZ (IC50 = 72 microM) congruent to PZ (IC50 = 72 microM). Anesthetics and other phenothiazines with weak anticalmodulin activity had no effect on secretory parameters. In the presence of histamine, further addition of isobutylmethylxanthine (IBMX, a phosphodiesterase inhibitor) plus dibutyryl cAMP (DBcAMP), IBMX alone, or forskolin (a specific activator of adenylate cyclase) to phenothiazine-inhibited tissues caused full resumption of secretory activity. If TFP (50 microM) was added before stimulation with histamine, the normal increases in tissue cAMP content (which occurs primarily in oxyntic cells), oxyntic cell apical membrane elaboration (morphometric analysis of electron micrographs), and H+ secretion were all blocked. Subsequent addition of IBMX or IBMX plus DBcAMP completely reversed the TFP effect. These results indicate that the histamine-sensitive adenylate cyclase may be the site of TFP inhibition and Ca2+-calmodulin regulation; since these drugs inhibited stimulation by DBcAMP plus IBMX, they may also be exerting additional effects distal to cAMP generation.

Bullfrog dorsal root ganglion cells having tetrodotoxin-resistant spikes are endowed with nicotinic receptors

1989 ◽  
Vol 62 (3) ◽  
pp. 657-664 ◽  
Author(s):  
K. Morita ◽  
Y. Katayama
Keyword(s):  
Dorsal Root Ganglion ◽  
Conduction Velocity ◽  
Dorsal Root ◽  
Time Course ◽  
Ganglion Cells ◽  
Reversal Potential ◽  
Membrane Resistance ◽  
Fast Response ◽  
Dorsal Root Ganglion Cells

1. Intracellular recordings were made from bullfrog dorsal root ganglion (DRG) neurons in vitro. They were divided into three types, As, Ar, and C, according to their conduction velocity and their sensitivity to tetrodotoxin [TTX (less than or equal to 1 microM)]; an As neuron had a fast conduction velocity (13-50 m/s, mean = 31 m/s, n = 73) and TTX-sensitive sodium soma spikes: an Ar neuron showed a fast conduction velocity (4-28 m/s, mean = 14 m/s, n = 52) and TTX-resistant sodium soma spikes; and a C neuron had a slow conduction velocity (0.16-0.8 m/s, mean = 0.4 m/s, n = 49) and TTX-resistant sodium-calcium soma spikes. 2. Superfusion of acetylcholine [ACh (0.3 microM-1 mM)] produced a fast depolarization in 70% of Ar and in 50% of C neurons. No As neuron showed a fast depolarization in response to ACh. The ACh-induced fast response persisted in calcium-free or TTX-containing solutions. 3. The response in both Ar and C neurons was similar except in time course; the response was always more rapid in C than in Ar neurons. The response was always associated with a decreased membrane resistance and reversed in polarity at about -30 mV. The reversal potential varied with both sodium and potassium concentrations of the superfusing solutions. 4. Nicotine, (+)-tubocurarine [(+)-TC], and hexamethonium reversibly blocked the ACh fast response.(ABSTRACT TRUNCATED AT 250 WORDS)

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