Vasoactive intestinal polypeptide regulation of rabbit renal adenylate cyclase activity in vitro.

XVe have previously reported to the Society the localization of fl-adrenoceptor subtypes in rat urinary bladder (Morrison et al. 1986). Using quantitative lightmicroscopic autoradiographv. changes in the density and distribution of f,-adrenoceptors in the bladder following both afferent and autonomic denervation were studied.Bladders were obtained from female XVistar rats (250-300 g) Afferent denervated bladders were obtained from rats treated neonatally with capsaicin. Unilateral and bilateral surgically denervated bladders were taken 14 days after nerve transection (halothane anaesthesia). Studies were performed on three animals from each group.The tissue was snap-frozen in Arcton 12 cooled to -196 'C. Tissue sections, 20 ,am thick, were cut on a cryostat and thaw-mounted onto poly-1-lysine coated slides. The tissue sections were incubated with [I251]iodocyanopindolol for 2 h at 37 'C. The distribution of the/,1-and f82-adrenoceptor subtypes were respectively determined by incubating with radioligand in the presence of either 10' m ICI 118,551 (a selective fl2-antagonist) or 10-7 m betaxolol (a selective /11-antagonist). Non-specific binding accounted for less than 5 % of total. Autoradiograms were generated as described by Carstairs et al. (1985). Autoradiographic grain density over sections of bladder dome was quantified using a Lietz MPV densitometer; quantification was performed on 35 sections from each bladder.In bladders from control animals ,-adrenoceptors were present over both the smooth muscle and epithelium, the /12-subtype accounting for 80% of the smooth muscle and 90 % of the epithelial adrenoceptors. Neonatal capsaicin treatment resulted in bladder hypertrophy, however there was no change in the densities of either /l3-or /12-adrenoceptors in the bladder. Unilateral denervation produced no hypertrophy, but there was a 2-6-fold increase in ,%-receptor density in the smooth muscle. Following bilateral denervation, hypertrophy was marked and resulted in an approximate 3-fold increase in the sectional area of smooth muscle on each slide. The density of /1-adrenoceptors per unit area was unchanged relative to controls, but 82-adrenoceptor density increased by 25 %. Epithelial /ll-adrenoceptor density increased 2 2-fold following unilateral denervation and 6 3-fold following bilateral denervation. Changes resulting from unilateral denervation were not restricted to the side of the lesion. It is proposed that changes in /I-adrenoceptor density following denervation reflect an upregulation of receptor number following loss of endogenous catecholamine.\N'ork supported bY the WN'ellcome Trust.

Section: P Proceedings Of the Physiological Societymentioning

confidence: 99%

“…Tissue was immediately chilled and snap frozen in liquid nitrogen. Homogenates of renal tissue and plasma membranes were prepared, and hormone-stimulated AC activity was measured as previously described (Griffiths & Simmons, 1987).…”

Section: P Proceedings Of the Physiological Societymentioning

confidence: 99%

Proceedings of the Physiological Society, 19‐20 May 1989, Leeds Meeting: Communications

1989

“…It appears that, whereas in our previous study (Law & Turner, 1987) cellvolume maintenance was effected by a metabolic increase in cellular n.p.s., maintenance under the conditions of this investigation was at least in part due to cellular uptake of Na dependent upon external AIB. Vasoactive intestinal peptide (VIP) has been shown to stimulate adenylate cyclase activity in plasma membranes from rabbit renal cortex and medulla (Griffiths & Simmons, 1987). In order to determine the precise location of VIP-responsive segments along the renal tubule we have determined adenylate cyclase activity (AC) using a micromethod in identified portions of individual renal tubular segments microdissected from collagenase-treated rabbit kidneys (Morel, Charbardes & Imbert-Teboul, 1978).…”

Section: Physiological Society Septemiber 1987mentioning

confidence: 99%

Proceedings of the Physiological Society, 18‐19 September 1987, Cambridge Meeting: Communications

1988

M13 9PTInteractions have been described between glucose metabolism and gastric function. For example, Davenport (1950) first reported that increased glucose concentration in stomach perfusate caused an increase in gastric acid secretion. Conversely, gastrin affects glucose metabolism (Unger, Ketterer, Duprez & Eisentraut, 1967;Hansky, Soveny & Korman, 1973;Ibu, Amure & Watson, 1975;Ibu, 1985). However, the effects of the hyperglyeaemia of diabetes mellitus on gastric acid secretion have not yet been elucidated.Male Sprague-Dawley albino rats (250-300 g) were made diabetic by a single intraperitoneal (i.P.) injection of 60 mg kg-' body weight streptozotocin (STZ) freshly prepared in citrate buffer. Control rats were injected with citrate buffer alone. Diabetes was detected 24 h after STZ injection by glycosuria and confirmed by raised plasma glucose 2 weeks after STZ injection. On this day the rats were anaesthetized with 110 mg kg-1 body weight Inactin injected i.P. and surgically prepared for stomach perfusion by the modified method of Ghosh & Schild (1958). Normal saline (0-9 % NaCl) was infused at 75 ,I min-' for 30 min followed by randomized 1 h infusion periods of pentagastrin (Sigma) either 0 4 ,jg, 0-8 jug or 1 6 ,ug h-1 100 gb ody weight, with 30 min control collections between the doses. Gastric effluent samples were collected in 10 min aliquots and titrated to a phenolphthalein endpoint.Plasma glucose levels (mM) were 5-6 + 0-5 and 33.9 + 3.5 for control and diabetic rats respectively. Basal acid output (mM h-1) was lower in diabetic rats (1I0+0-05) than in control rats (1-36+0-06). However, pentagastrin evoked a greater secretory effect (mM h-') in the diabetic rats (2-79 + 0-26, 3-89 + 0 45, 6-99 + 0-36 at the three doses of pentagastrin used as compared with 2-02 + 0 13, 2-41 + 0-18 and 3.77 + 0 33 in the control rats), P < 0-01, n = 6, paired t test.It is inferred that the lower basal acid output in STZ diabetic rats may be due to the chronic hyperglycaemic state, but that the sensitivity of these diabetic rats to pentagastrin is enhanced.

“…Preparation of plasma membranes from cortical and medullary tissue Methods used were similar to those previously described for the preparation of plasma membranes from rabbit kidneys (Griffiths & Simmons, 1987). Tissue samples were placed in ice-cold assay buffer containing sucrose (0 25 M), Tris-HEPES (2 mM), phenylmethylsulphonyl fluoride (0 1 mM), EDTA (1 mM), pH 7-4; and processed on an ice-cool plate.…”

Section: Renal Materialsmentioning

confidence: 99%

“…(Griffiths & Simmons, 1987), cat (Griffiths, Rivier & Simmons, 1988 a) and dog (Griffiths, Rugg & Simmons, 1989a). Furthermore, VIP-sensitive adenylate cyclase is found to be located within rabbit kidney in glomeruli (Griffiths & Simmons, 1987) and in specific and distinctive regions of the nephron (in particular the bright portion of the distal convoluted tubule and the inner stripe of the outer medullary collecting tubule; Griffiths, Chabardes, Imbert-Teboul, Siaume-Perez, Morel & Simmons, 1988 b). Specific VIP receptors have been demonstrated using both 1251-labelled VIP binding to isolated feline plasma membranes (Griffiths & Simmons, 1988) and by 1251-labelled VIP autoradiography in rat kidney sections (Magistretti, Hof, Martin, Dietl & Palacios, 1988).…”

Section: Introductionmentioning

confidence: 99%

Vasoactive intestinal peptide stimulation of human renal adenylate cyclase in vitro.

Charlton

Neal

Simmons

1990

Self Cite

3. Half-maximal stimulation of human renal cortical plasma membrane adenylate cyclase was observed with a mean value of 35 nM-VIP.4. The stimulation of renal adenylate cyclase by VIP appeared to be specific because stimulation by glucagon was additive to that obtained with VIP, and the VIP receptor antagonist (4 Cl-D-Phe6, Leul7)-VIP inhibited the VIP-dependent stimulation of adenylate cyclase activity.