Roles of Dopaminergic D1 and D2 Receptors in Catecholamine Release from the Rat Adrenal Medulla

The aim of the present study was designed to establish comparatively the inhibitory effects of D1-like and D2-like dopaminergic receptor agonists, SKF81297 and R(-)-TNPA on the release of catecholamines (CA) evoked by cholinergic stimulation and membrane depolarization from the isolated perfused model of the rat adrenal medulla. SKF81297 (30 micrometer) and R-(-)-TNPA (30 micrometer) perfused into an adrenal vein for 60 min, produced great inhibition in the CA secretory responses evoked by ACh (5.32x10(-3) M), DMPP (10(-4) M), McN-A-343 (10(-4) M), high K+ (5.6x10(-2) M), Bay-K-8644 (10 micrometer), and cyclopiazonic acid (10 micrometer), respectively. For the release of CA evoked by ACh, high K+, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid, the following rank order of inhibitory potency was obtained: SKF81297>R-(-)-TNPA. However, R(+)-SCH23390, a selectve D1-like dopaminergic receptor antagonist, and S(-)-raclopride, a selectve D2-like dopaminergic receptor antagonist, enhanced the CA secretory responses evoked by ACh, high K+, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid only for 0~4 min. The rank order for the enhancement of CA release evoked by high K+, McN-A-343 and cyclopiazonic acid was R(+)-SCH23390>S(-)-raclopride. Also, the rank order for ACh, DMPP and Bay-K-8644 was S(-)-raclopride > R(+)-SCH23390. Taken together, these results demonstrate that both SKF81297 and R-(-)-TNPA inhibit the CA release evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors and the membrane depolarization from the isolated perfused rat adrenal gland without affecting the basal release, respectively, but both R(+)-SCH23390 and S(-)-raclopride facilitate the CA release evoked by them. It seems likely that the inhibitory effects of SKF81297 and R-(-)-TNPA are mediated by the activation of D1-like and D2-like dopaminergic receptors located on the rat adrenomedullary chromaffin cells, respectively, whereas the facilitatory effects of R(+)-SCH23390 and S(-)-raclopride are mediated by the blockade of D1-like and D2-like dopaminergic receptors, respectively: this action is possibly associated with extra- and intracellular calcium mobilization. Based on these results, it is thought that the presence of dopaminergic D1 receptors may play an important role in regulation of the rat adrenomedullary CA secretion, in addition to well-known dopaminergic D2 receptors.

Influence of Cilnidipine on Catecholamine Release in the Perfused Rat Adrenal Medulla

The present study was attempted to investigate the effect of cilnidipine (FRC-8635), which is a newly synthesized novel dihydropyridine (DHP) type of organic Ca2 channel blockers, on secretion of catecholamines (CA) evoked by acetylcholine (ACh), high K, DMPP and McN-A-343 from the isolated perfused rat adrenal gland. Cilnidipine (1~10microM) perfused into an adrenal vein for 60 min produced relatively dose- and time-dependent inhibition in CA secretory responses evoked by ACh (5.32 10 3 M), DMPP (10 4 M for 2 min) and McN-A-343 (10 4 M for 2 min). However, lower dose of cilnidipine did not affect CA secretion by high K (5.6 10 2 M), higher dose of it reduced greatly CA secretion of high K. Cilnidipine itself did fail to affect basal catecholamine output. In the presence of cilnidipine (10microM), the CA secretory responses evoked by Bay-K-8644 (10microM), an activator of L-type Ca2 channels and cyclopiazonic acid (10microM), an inhibitor of cytoplasmic Ca2 -ATPase were also inhibited. Moreover, omega-conotoxin GVIA (1microM), a selective blocker of the N-type Ca2 channels, given into the adrenal gland for 60 min, also inhibited time-dependently CA secretory responses evoked by Ach, high K, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid. Taken together, these results demostrate that cilnidipine inhibits CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors from the isolated perfused rat adrenal gland without affecting the basal release. However, at lower dose, cilnidipine did not affect CA release by membrane depolarization while at larger dose inhibited that. It seems likely that this inhibitory effect of cilnidipine is exerted by blocking both L- and N-type voltage-dependent Ca2 channels (VDCCs) on the rat adrenomedullary chromaffin cells, which is relevant to inhibition of both the Ca2 influx into the adrenal chromaffin cells and intracellular Ca2 release from the cytoplasmic store. It is thought that N-type VDCCs may play an important role in regulation of CA release from the rat adrenal medulla.

A Case of Congenital Cystic Adenomatoid Malformation of the Lung / 대한내과학회지

Congenital cystic adenomatoid malformation(C.C. A.M.) is a rare variant of congenital pulmonary cystic diseases. C.C.A.M. was first distinguished from other pulmonary cystic lesions by Ch`in and Tang in 1949. It is characterized by cessation of bronchiolar maturation with an overgrowth of mesenchymal elements and proliferation of polypoid glandular tissue in the absence of normal alveolar differentiation. In 80% to 95% of cases, C.C.A.M. of the lung is confinded to a single lobe and there is no lobe predilection and right and left predominance. The clinical presentation may be widely variable, ranging from intrauterine fetal death secondary to nonimmune hydrops fetalis to discovery in childhood after recurrent pulmonary infections. Definitive treatment is removal of affected lobe. In rare instances, there is cases of myxosarcoma, embryonal rhabdomyosarcoma. Bronchoalveolar carcinoma arising in C.C.A.M.. So, resection is recommended even if they are asymtomatic. We have experienced a case of congenital cystic adenomatoid malformation (type II) of the lung in 15 year old man with pneumonia. After the improvement of pneumonia, surgical operation was performed. A brief review of the related literature is presented.

A case of mycoplasma pneumonia which progressed to ARDS / 결핵

Mycoplasma Pneumonia is a main cause of primary atypical pneumonia and may present in a variety of ways. One auther has stated that the infiltrate is of a lobar segmental type, while others have found the infiltrates to be mainly reticular or interstitial. We experienced a case of mycoplasama pneumonia, whic h progressed to ARDS pattern rapidly and recovered completely after ventilator care.

A case of single cervical tuberculous cold abscess associated with multi-loculated tuberculous pleurisy / 결핵

St. Francisco General Hospital, Seoul, Korea. Although the incidence of pulmonary tuberculosis is declining, the number of extrapulmonary tuberculosis has remained constant. Tuberculous Lymphadenitis accounts for over 50% of total inflammatory lymphadenitis and the most common site is cervical lymph node. We report a case of single cervical tuberculous cold abscess associated with multiloculated and septated tuberculous pleurisy. Intracavitary urokinase instillation via percutaneous catheter is indicated in loculated and septated pleural effusion. And our result was satisfactory without complication.