Expression of Rat cGMP‐Binding cGMP‐Specific Phosphodiesterase mRNA in Purkinje Cell Layers During Postnatal Neuronal Development

Abstract

The cDNA encoding rat cGMP-binding, cGMP-specific phosphodiesterase (cGB-PDE) was isolated from a rat lung cDNA library. Although the deduced amino acid sequence showed 93.4% similarity with that of bovine cGB-PDE, the N-terminal portion of rat cGB-PDE was extremely different from that of bovine. Northern blot analysis indicated that cGB-PDE transcripts in rats were expressed not only in aorta and lung, but also in several other tissues including cerebellum. In situ hybridization analysis demonstrated that cerebellar expression of cGB-PDE was confined to Purkinje cell layers in adult rats. To clarify the role of cGB-PDE in the cerebellum, we investigated expression of cGB-PDE mRNA in rats of various ages. cGB-PDE mRNA was not observed in the cerebellum of newborn rats, but levels of a cGB-PDE mRNA were markedly increased between 4 days and 28 days of age and reached a maximum in eight-week-old rats. In this study, we suggest that cGB-PDE plays important roles not only in regulating the relaxation of vascular vessels, but also in establishing neuronal networks in the cerebellum at an early postnatal stage. In addition the NO/cGMP/cGB-PDE pathway appears to be essential for the induction of long-term depression.

Immunohistochemical Localization of cGMP-binding cGMP-specific Phosphodiesterase (PDE5) in Rat Tissues

“…An increase in cGMP, via activation of parallel fibers and climbing fibers, evokes long-term depression in Purkinje cells. In situ hybridization demonstrated that the cerebellar expression of PDE5 transcripts is limited to Purkinje cells (Kotera et al 1997). Local administration of zaprinast, a PDE5 inhibitor, leads to an increase of cGMP release from cerebellar slices and promotes induction of cerebellar long-term depression in rat cerebellar slices when paired with parallel fiber stimulation (Hartell 1996).…”

“…We have isolated human, canine, and rat PDE5 cDNAs from lung cDNA libraries and here described cDNAs encoding two variants of PDE5 (PDE5A1 and PDE5A2) in these species (Kotera et al 1997. Our studies revealed high levels of PDE5 transcripts in rat cerebellum and intestine in addition to tissues containing VSMCs.…”

“…Cytosolic extracts of COS-7 cells expressing recombinant human PDE5A1 and recombinant rat PDE5A2 proteins were prepared as described previously (Kotera et al 1997;Yanaka et al 1998). Male Sprague-Dawley rats at 10 weeks of age (Japan SLC; Shizuoka, Japan) were anesthetized with sodium pentobarbital before various tissues were excised.…”

“…In human tissues, PDE5A1 transcripts were particularly abundant in the pancreas . In situ hybridization showed that rat PDE5 transcripts were localized to the Purkinje cells in the cerebellum (Kotera et al 1997). However, we failed to reveal cellular localization of PDE5, except for the brain, by in situ hybridization.…”

Acute and Chronic Effects of T-1032, a Novel Selective Phosphodiesterase Type 5 Inhibitor, on Monocrotaline-Induced Pulmonary Hypertension in Rats.

“…8,9) PDE5 is abundantly expressed in some specific tissues, including the lung and pulmonary artery. [10][11][12] Therefore, the inhibition of PDE5 is considered to produce an increase in cGMP levels in the lung and pulmonary artery. It has been reported that PDE5 inhibitors such as zaprinast, E-4021 and sildenafil preferably dilate the pulmonary artery in vivo and in vitro experimental conditions.…”