Particulate guanylate cyclase and adenylate cyclase activities after activation with various agents in rabbit platelets. An ultracytochemical study

Abstract

The cytochemical localization of particulate guanylate cyclase and adenylate cyclase activities in rabbit platelets were studied after stimulation with various agents, at the electron microscope level. In the presence of platelet aggregating agents such as thrombin and ADP, the particulate reaction product of guanylate cyclase activity was detectable on plasma membrane and on membranes of the open canalicular system. In contrast, samples incubated with platelet-activating factor showed no activation of the cyclase activity. Atrial natriuretic factor stimulated the particulate guanylate cyclase. The ultracytochemical localization of this activated cyclase was the same as that of thrombin- or ADP-stimulated guanylate cyclase. Adenylate cyclase activity was studied in platelets incubated with prostaglandin E1 plus or minus insulin. The enzyme reaction product was found at the same sites where guanylate cyclase was detected. Therefore guanylate and adenylate cyclase activities do not seem to be preferentially localised in platelet membranes.

Ultracytochemical localization of particulate guanylate cyclase after stimulation with natriuretic peptides in lamb olfactory mucosa

“…Similar to previous observations on ultracytochemical localization of particulate GC activity (Rambotti et aI., 1987(Rambotti et aI., , 1988Spreca et al, 1989;Rambotti et al, 1990;Spreca et al,, 1991), here we provide morphological evidence that GC reaction product was detected on plasma membranes even if there is some localization of GC reaction product on intracellular membranes. Recently we detected the presence of rANF and pBNP GC capable of stimulating on intracellular membranes in rat adrenal gland (Rambotti et aL, 1993) and in rat neurohypophysis (Rambotti et al, 1994).…”

Ultracytochemical localization of particulate guanylate cyclase in rat adrenal gland exposed to stimulation by porcine brain natriuretic peptide

“…Unlike previous data on GC activity in other tissues where the GC reaction product was detected prevalently on plasma membranes (Rambotti et al, , 1988Spreca el al., 1989;Rambotti et al, 1990;Rambotti & Spreca, 1991;Spreca et al, 1991), in the present study the GC reaction product was detected on intracellular membranes of cortical and medullary cells in adrenal gland. This is in agreement with ultrastructural autoradiographic data on internalization of ANF in rat adrenal gland (Morel eta]., 1988(Morel eta]., , 1989.…”

“…It has been detected in soluble form in the cytosolic fraction of homogenates as well as associated with cellular membranes (particulate form) in many tissues of most animal species (for a review see Tremblay et al, 1988). ANFstimulated GC has been described ultracytochemically in several cell types of rat kidney and lung, and in rabbit platelets (Rambotti et al, 1990;Rambotti & Spreca, 1991;Spreca et al, 1991).…”