Existence of ATP-evoked ATP release system in smooth muscles

Effects of stable ATP analogs such as alpha,beta-methylene ATP (alpha,beta-mATP) and beta,gamma-methylene ATP (beta,gamma-mATP) on ATP release and contractile response were evaluated in the vas deferens and ileal longitudinal muscles of guinea pig. In these smooth muscles, administration of alpha,beta-mATP (10, 30 or 100 microM) produced an ATP release accompanied by a transient contraction, but alpha,beta-methylene ADP (30 or 100 microM) or adenosine (30 microM) failed to elicit both the ATP release and the contraction. However, the peak responses of ATP release and contraction to alpha,beta-mATP (100 microM) in the vas deferens appeared around 2 min and 2.62 sec, respectively, after the injection of the drug. Beta,gamma-mATP (10 or 100 microM) caused an ATP release from the vas deferens. The ATP release as well as the contraction evoked by alpha,beta-mATP or beta,gamma-mATP were effectively inhibited by 300 microM suramin, a P2 purinoceptor antagonist. By contrast, ATP release and contractile response to norepinephrine in the vas deferens and those to bethanechol in the ileum were virtually unaffected by this antagonist. Veratridine and ouabain at (30 or 100 microM) caused markedly acetylcholine release from the ileum and norepinephrine release from the vas deferens, respectively. However, alpha,beta-mATP, even in a high concentration of 100 microM, did not elicit any release of acetylcholine or norepinephrine. These findings suggest that alpha,beta-mATP and probably beta,gamma-mATP evoke ATP release from not neuronal but mainly smooth muscular sites by activating suramin-sensitive P2x receptors, implying that "ATP-evoked ATP release system" exists.

Development of a new host vector system in mycobacteria

The hybrid plasmid pYT72/pYT92 constructed from an Escherichia coli plasmid pACYC177 and mycobacterial plasmid pMSC262 isolated from Mycobacterium scroflaceum strain W262 transformed both E. coli and BCG. Phage-sensitive mutants S-10 and S-20 isolated from BCG Tokyo strain showed higher frequency of transformation than the wild-type strain. Frequency of transformation was dependent on age of the culture and the electroporation condition used. Several deletion mutants were generated from pYT72/92 to determine the minimum region for the replication in the mycobacteria. A 2.3-kb fragment of pMSC262 was found to contain an essential region. Using this fragment and pACYC177, a small shuttle vector pYT937 containing two drug-resistance markers, kanamycin- and ampicillin-resistance, was constructed. pYT937 contains AatII, BamHI, BbvII, GsuI, HincII, PstI, ScaI and XbaI cloning sites.

Clinical usefulness of serum squamous cell carcinoma antigen for early detection of squamous cell carcinoma arising in mature cystic teratoma of the ovary

Squamous cell carcinoma arising in mature cystic teratoma of the ovary is rarely diagnosed preoperatively. We measured the pre-treatment serum levels of squamous cell carcinoma antigen in three stage I patients in order to evaluate its usefulness as a tumor marker for early detection of the disease. The serum levels were elevated in each case, to 26.9, 5.1, and 3.2 ng/mL, respectively, and rapidly dropped to within the normal range after treatment. All patients are recovered and show no evidence of recurrence, and the levels of serum squamous cell carcinoma antigen have remained within normal limits. These results suggest that measurement of the serum squamous cell carcinoma antigen level may be useful in diagnosing an early-stage primary squamous cell carcinoma arising in a mature cystic teratoma of the ovary. An elevated preoperative serum level of squamous cell carcinoma antigen may indicate the need for a rapid pathologic examination of the tumor to look for malignant elements and may influence the surgical regimen.

[Establishment of a host-vector system in Mycobacterium bovis BCG]

The recombinant plasmids, pYT72 and pYT92, were generated from a mycobacterial plasmid, pMSC262, and a Escherichia coli plasmid, pACYC177. These plasmids were capable of replication, and of stable maintainance in Mycobacterium bovis BCG when introduced by electroporation technique. Efficiency of transformation was about 10(4) transformants/micrograms DNA, and was the highest in the phage sensitive mutants (S-10, S-20) isolated from BCG Tokyo strain. We have also isolated transformable mutants from rapidly growing bacterium, M. smegmatis strains Jucho and TMC1533. By isolating deletion mutants from pYT72/92, we could determine the location of replication region of pMSC262 within a 2.3 kb Pst I-Hind III fragment. Using this fragment, we constructed "mini" shuttle plasmid pYT937 (5.9 kb in size) which possesses kanamycin and ampicillin resistance markers and replicates in both E. coli and Mycobacterium. Nucleotide sequence analysis of the replication region revealed that there are 2 potential coding regions which contain more than 200 amino acids. The largest one (ORF1) which codes 311 amino acids, however, lacks Shine-Dalgarno like sequence in the upstream and therefore may not be functional. The other coding region (ORF2) contains 260 amino acids and was preceded by Shine-Dalgarno like sequence. Upstream of the ORF2, there were several repeat sequences which may be important in the plasmid replication. GC content of the 2.3 kb fragment was 69.8%.

Granulocyte-macrophage colony-stimulating factor promotes the proliferation of human alveolar macrophages in vitro

The effects of granulocyte-macrophage (GM-CSF) or macrophage-CSF on in vitro proliferation of human alveolar macrophages (AM) were evaluated. AM of healthy volunteers incubated with recombinant human GM-CSF revealed incorporation of [3H]thymidine in vitro. The maximum incorporation was observed at 20 U/ml of GM-CSF on day 3. The proportion of proliferating cells incubated with 20 U/ml of GM-CSF from day 3 to day 4 was 8 to 11% of the total, whereas 3 to 5% of cells proliferated without GM-CSF. The number of cell nuclei increased 1.30- to 1.68-fold in the initial 7 days during incubation with 20 U/ml of GM-CSF, whereas there was a 1.07- to 1.13-fold increase without GM-CSF. Conditioned media obtained by the incubation with human lung tissue exhibited similar effects as recombinant human GM-CSF on macrophages. The effects were completely abrogated by antibody against human GM-CSF. Immunohistochemically, GM-CSF was detected in lung cells including AM, alveolar epithelium, alveolar interstitial cells, and endothelial cells. In contrast, recombinant macrophage-CSF did not induce the proliferation of human AM, although it has been known to promote the proliferation of murine AM. These observations suggest that GM-CSF plays an important role among the regulatory factors that locally support the population of AM in human lungs.

Granulocyte-macrophage colony-stimulating factor promotes the proliferation of human alveolar macrophages in vitro

The effects of granulocyte-macrophage (GM-CSF) or macrophage-CSF on in vitro proliferation of human alveolar macrophages (AM) were evaluated. AM of healthy volunteers incubated with recombinant human GM-CSF revealed incorporation of [3H]thymidine in vitro. The maximum incorporation was observed at 20 U/ml of GM-CSF on day 3. The proportion of proliferating cells incubated with 20 U/ml of GM-CSF from day 3 to day 4 was 8 to 11% of the total, whereas 3 to 5% of cells proliferated without GM-CSF. The number of cell nuclei increased 1.30- to 1.68-fold in the initial 7 days during incubation with 20 U/ml of GM-CSF, whereas there was a 1.07- to 1.13-fold increase without GM-CSF. Conditioned media obtained by the incubation with human lung tissue exhibited similar effects as recombinant human GM-CSF on macrophages. The effects were completely abrogated by antibody against human GM-CSF. Immunohistochemically, GM-CSF was detected in lung cells including AM, alveolar epithelium, alveolar interstitial cells, and endothelial cells. In contrast, recombinant macrophage-CSF did not induce the proliferation of human AM, although it has been known to promote the proliferation of murine AM. These observations suggest that GM-CSF plays an important role among the regulatory factors that locally support the population of AM in human lungs.

Pathology of the fallopian tube

Tubal carcinoma and serous adenocarcinoma of the ovary are remarkably similar in biologic characteristics and tumor markers, which suggests that the management for tubal carcinoma would be based on that for ovarian carcinoma. The cases with rare histologic features, including endometrioid carcinoma, mixed müllerian tumor, and malignant fibrous histiocytoma have been reported. In the genesis of tubal pregnancy, microscopic evidence of silent inflammation has attracted special interest recently. With the development of sophisticated diagnostic tests and the progress of medical management, it has become possible to treat unruptured tubal pregnancies by pharmacologic approaches, laparoscopy, or transvaginal sonographic control. This review briefly outlines the conspicuous pathologic and etiologic features of neoplasms, ectopic pregnancy, and abnormality of the fallopian tube, and discusses some recent observations regarding these disorders.

[A case of bacterial aneurysm following Hardy's operation]

Intracranial mycotic aneurysm of extravascular origin is reported. A 64 year-old male developed headache and visual disturbance. Computed Tomography (CT) revealed high density mass lesion with contrast enhancement in the intra- and suprasellar lesion. He was then admitted to our hospital under the diagnosis of pituitary adenoma. But he suddenly complained of headache and loss of vision during hospitalization. An emergency operation using the transsphenoidal approach was performed. The pathological diagnosis was craniopharyngioma. Postoperative radiation therapy was carried out using a tumor dose of 50Gy. Two months after the operation, he suffered from rhinorrhea and high fever. He was admitted again and treated with high doses of antibiotics. Two weeks after admission, he suddenly lost consciousness. A CT scan revealed an aneurysm of the anterior temporal artery. Immediately, removal of the hematoma and resection of the aneurysm were performed. Microscopic examination showed that inflammatory cells had infiltrated the aneurysmal wall, and lymphocytes and plasma cells had gathered around the microabscess. This rare case is discussed with other related cases in the literature.

Preexposure of macrophages to low doses of lipopolysaccharide inhibits the expression of tumor necrosis factor-alpha mRNA but not of IL-1 beta mRNA

LPS is known to be a potent activator of macrophages and induces the production of TNF-alpha and IL-1. However, the signaling events and regulatory mechanisms required for the activation of macrophages by LPS have not been resolved precisely. We show that LPS modulates its own response in macrophages. Proteose peptone-induced murine peritoneal macrophages (P-PEM) produce significant amount of TNF-alpha and IL-1 after stimulation with LPS. However, preexposure of macrophages to low doses (less than 1 ng/ml) of LPS renders them refractory to stimulation by a second round of LPS, as evaluated by production of TNF-alpha. The loss of sensitivity to a second round of LPS was selective for TNF-alpha production as the LPS-primed macrophages retained the ability to produce IL-1. Northern blot analysis was performed with total RNA obtained from control and LPS- (1 ng/ml) primed P-PEM after 3-h stimulation with a second round of LPS. The expression of TNF-alpha mRNA was inhibited in LPS-primed P-PEM, whereas the expression of IL-1 beta mRNA was the same in control and LPS-primed P-PEM, consistent with the data of biologic activities of these two cytokines. Zymosan-induced TNF-alpha production was the same in control and LPS-primed macrophages, indicating that not all of the pathways required for TNF-alpha production were affected by LPS priming. Monokines such as human (h) rIL-1 alpha, hrTNF-alpha, hrIL-6, and murine rIFN-beta could not substitute for the action of low doses of LPS, and addition of indomethacin could not restore TNF-alpha production. These results suggest that exposure of macrophages to low doses of LPS suppresses the production of TNF-alpha, but not of IL-1, by inhibiting the expression of mRNA through a noncyclooxygenase-dependent mechanism. Thus, LPS-induced production of TNF-alpha and IL-1 in macrophages are differently regulated.

Preexposure of macrophages to low doses of lipopolysaccharide inhibits the expression of tumor necrosis factor-alpha mRNA but not of IL-1 beta mRNA

LPS is known to be a potent activator of macrophages and induces the production of TNF-alpha and IL-1. However, the signaling events and regulatory mechanisms required for the activation of macrophages by LPS have not been resolved precisely. We show that LPS modulates its own response in macrophages. Proteose peptone-induced murine peritoneal macrophages (P-PEM) produce significant amount of TNF-alpha and IL-1 after stimulation with LPS. However, preexposure of macrophages to low doses (less than 1 ng/ml) of LPS renders them refractory to stimulation by a second round of LPS, as evaluated by production of TNF-alpha. The loss of sensitivity to a second round of LPS was selective for TNF-alpha production as the LPS-primed macrophages retained the ability to produce IL-1. Northern blot analysis was performed with total RNA obtained from control and LPS- (1 ng/ml) primed P-PEM after 3-h stimulation with a second round of LPS. The expression of TNF-alpha mRNA was inhibited in LPS-primed P-PEM, whereas the expression of IL-1 beta mRNA was the same in control and LPS-primed P-PEM, consistent with the data of biologic activities of these two cytokines. Zymosan-induced TNF-alpha production was the same in control and LPS-primed macrophages, indicating that not all of the pathways required for TNF-alpha production were affected by LPS priming. Monokines such as human (h) rIL-1 alpha, hrTNF-alpha, hrIL-6, and murine rIFN-beta could not substitute for the action of low doses of LPS, and addition of indomethacin could not restore TNF-alpha production. These results suggest that exposure of macrophages to low doses of LPS suppresses the production of TNF-alpha, but not of IL-1, by inhibiting the expression of mRNA through a noncyclooxygenase-dependent mechanism. Thus, LPS-induced production of TNF-alpha and IL-1 in macrophages are differently regulated.

Effect of a synthetic adjuvant for inducing anti-tumour immunity

An acylated derivative of muramyl dipeptide (MDP), 6-O-(2-tetradecyl-hexadecanoyl)-muramyl-dipeptide (B30-MDP) is a strong adjuvant effective in inducing cell-mediated immunity. We used B30-MDP as an adjuvant for induction of anti-tumour immunity. Guinea-pigs which were injected repeatedly with a mixture of X-ray-treated leukaemic cells and B30-MDP dissolved in phosphate buffered saline resisted a challenge of leukaemia cells and showed no sign of leukocytosis. The immunity induced was tumour-specific and retained for more than 100 days. These results suggest that B30-MDP is useful as a simple but potent immunotherapeutic tool.

Multiple primary brain tumors of different histological types--report of two cases

Simultaneous development of histologically different primary brain tumors aside from phacomatoses or previous irradiation is rare, and its preoperative diagnosis is still difficult. We report two such cases, a 49-year-old male with an acoustic neurinoma and a cerebellar hemangioblastoma and a 69-year-old female with a parietal convexity meningioma and an ipsilateral frontal lobe astrocytoma. The tumors in the first case developed closely, so some local stimulation probably acted as a developmental factor. However, the tumors in the second case developed in distant areas and were considered coincidental.

[Entirely suprasellar symptomatic Rathke's cleft cyst]

Two rare cases of entirely suprasellar Rathke's cleft cyst were reported. Case 1. A 62-year-old man was admitted to our hospital on the 14th of January, 1988, complaining of headache and diplopia. A plain skull x-ray showed the sella turcica was normal. CT scan and MRI demonstrated a lesion mass located entirely in the suprasellar cistern. Right frontotemporal craniotomy was performed, and the cyst wall was resected subtotally. Microscopic sections of cyst wall showed ciliated single layer with focal stratified epithelium. Case 2. A 51-year-old man was hospitalized complaining of visual impairment in the left eye. Endocrinological examination showed no abnormalities. CT and MRI demonstrated a lesion mass located entirely in the suprasellar region. Right frontotemporal craniotomy was performed. The mass was opened and a large amount of yellowish fluid was released. Histologically, the specimens were simple ciliated cuboidal epithelium. Postoperative courses of these patients were uneventful. The findings on CT and MRI of the cases located entirely in the suprasellar region were varied. The histopathogenesis and embryological pathogenesis of Rathke's cleft cyst in the literature, particularly the entirely suprasellar type, were discussed.

Multiple brain tumors of different cell types with an unruptured cerebral aneurysm--case report

A rare case of coexistent Burkitt-type lymphoma and meningioma associated with an unruptured cerebral aneurysm is presented. A 49-year-old male complaining of headache and right hemiparesis was admitted to our hospital. Neuroradiological examination revealed a multinodular mass in the left frontal convexity and an unruptured cerebral aneurysm at the M1 portion of the left middle cerebral artery. He underwent an operation for tumor removal and aneurysm clipping. Histological examination revealed the tumor to be a typical meningotheliomatous meningioma without malignancy. However, a second operation was necessary for another tumor invading into the left frontal lobe, which proved to be a Burkitt-type lymphoma. The second tumor may have been resulted from irritative effect of the first tumor, but the aneurysm was considered purely coincidental.

[A case of intraosseous meningioma]

A case of intraosseous meningioma at the posterior fossa was reported. Intraosseous meningioma is very rate and only six cases have been reported in Japanese literature. A 64 year-old woman complained of progressive headache and was admitted to Ichinomiya Neurosurgical Hospital. On admission, neurological examination did not reveal any abnormalities. However, plain skull X-p showed a hyperostotic lesion in the right posterior fossa. CT scan demonstrated homogeneously enhanced mass by contrast medium. MRI showed a mass lesion of the posterior fossa on T1 and T2 weighted images. The right vertebral angiogram showed an avascular area in the right posterior fossa and no tumor stain. The tumor, which was partially attached to the underlying dura, was successfully removed surgically. The operative finding confirmed an intraosseous meningioma which had arisen from the right asterion. The post operative course was uneventful. Histological examination revealed fibroblastic meningioma.

Identification of a soluble IL-2 receptor beta-chain from human lymphoid cell line cells

A clone was isolated from the human lymphoid cell line YT that displayed IL-2R beta, and was found to express much higher levels of IL-2R beta than the original cells. Combining cell surface iodination, affinity labeling of the released soluble protein, and fluorescence sandwich-ELISA for both IL-2 and IL-2.(soluble)(s)IL-2R beta reactants revealed the presence of IL-2-binding protein in the culture supernatant as soluble forms of IL-2R beta. By using the fluorescence sandwich-ELISA elevated levels of sIL-2R beta were measured in culture supernatants of human T cell leukemia virus I positive T cell lines. In addition to this constitutive production of sIL-2R beta, normal PBMC could release low levels of IL-2R beta by stimulation with PHA. In contrast, this was not found in certain human T cell leukemia virus I negative T cell, B cell and macrophage lines. Immunoprecipitation of the soluble protein with IL-2R beta-specific mAb characterized it as an apparent 50- to 55-kDa molecule that is distinct from the 45-kDa soluble IL-2R alpha. Moreover, 10 to 15% of the total cell surface molecules were released into culture supernatants. These results suggest that the released IL-2R beta might serve as an immunoregulatory function in IL-2 dependent both normal and abnormal immune responses.

Identification of a soluble IL-2 receptor beta-chain from human lymphoid cell line cells

A clone was isolated from the human lymphoid cell line YT that displayed IL-2R beta, and was found to express much higher levels of IL-2R beta than the original cells. Combining cell surface iodination, affinity labeling of the released soluble protein, and fluorescence sandwich-ELISA for both IL-2 and IL-2.(soluble)(s)IL-2R beta reactants revealed the presence of IL-2-binding protein in the culture supernatant as soluble forms of IL-2R beta. By using the fluorescence sandwich-ELISA elevated levels of sIL-2R beta were measured in culture supernatants of human T cell leukemia virus I positive T cell lines. In addition to this constitutive production of sIL-2R beta, normal PBMC could release low levels of IL-2R beta by stimulation with PHA. In contrast, this was not found in certain human T cell leukemia virus I negative T cell, B cell and macrophage lines. Immunoprecipitation of the soluble protein with IL-2R beta-specific mAb characterized it as an apparent 50- to 55-kDa molecule that is distinct from the 45-kDa soluble IL-2R alpha. Moreover, 10 to 15% of the total cell surface molecules were released into culture supernatants. These results suggest that the released IL-2R beta might serve as an immunoregulatory function in IL-2 dependent both normal and abnormal immune responses.

Noninvasive estimation of the location of the end plate in the human masseter muscle using surface electromyograms with an electrode array

The purpose of this study was to estimate the location of the end plate in the masseter muscle, and to decide the appropriate position of surface electrodes for recording electromyograms (EMG) in humans. The subjects were 16 males who had no signs or symptoms of muscular disease. Identical electrode arrays were placed on the masseter muscles on each side. Each subject was asked to clench in the intercuspal position at various levels of maximum EMG amplitude. Eleven amplified EMGs were monitored simultaneously using a linear electrode array consisting of 12 stainless steel contacts. Various values were observed in different regions of the masseter muscle for the root mean square rectified EMG during brief isometric contraction. The superior region of the muscle had lower values than the inferior. The end-plate zone, which is in the center of the lower half of the masseter muscle, showed a lower amplitude than other regions. The propagation of motor unit action potentials was also observed. It was concluded that, aside from the end-plate zone, a position within the lower half of the muscle was most suitable for recording the surface EMG of the masseter muscle.

Immunotherapeutic potential in guinea-pig tumor model of deoxyribonucleic acid from Mycobacterium bovis BCG complexed with poly-L-lysine and carboxymethylcellulose

In vivo antitumor activity of a deoxyribonucleic acid fraction obtained from Mycobacterium bovis BCG (named MY-1) increased when it was complexed with poly-L-lysine (poly LL) solubilized by addition of carboxymethylcellulose (CMC). The complex of MY-1 and poly LL/CMC induced interferon in vivo at a low dose of MY-1 which alone exerted no IFN induction. With Line 10 hepatoma (L10) which is syngeneic with strain 2 guinea pigs, it was demonstrated that repeated intralesional injections of the complex resulted in delay of tumor growth and complete cure of animals from L10 tumor inoculated. Similar treatment of the animals with the same amount of MY-1 or poly LL/CMC alone had little therapeutic effect on the tumor growth.

Lack of response of murine peritoneal macrophages to in vitro activation by muramyl dipeptide (MDP). I. Macrophage activation by MDP is species dependent

Peritoneal exudate macrophages from mice, rats, and guinea pigs were assessed using six different parameters of macrophage activation to determine whether the cells were stimulated under similar experimental conditions. Peritoneal exudate macrophages from mice, irrespective of strain, were far less responsive to a variety of in vitro stimulatory effects of N-acetylmuramyl-L-alanyl-D-isoglutamine than those from rats or guinea pigs, while no significant differences were noted with the reactivity to stimulation by endotoxic lipopolysaccharide. We conclude that macrophage activation by MDP in vitro is species dependent.

Serial measurement of CA 125 in patients with primary carcinoma of the fallopian tube

Serial assay of serum CA 125 was carried out in five patients with advanced primary carcinoma of the fallopian tube. Pretreatmental levels of these patients were elevated, ranging from 145 to 535 U/ml (305 +/- 140.1, mean +/- SD). All patients showed rapid decreases in response to treatment; however, reelevations were noted in two patients concomitant with recurrence. In the remaining three patients, who are alive with no evidence of recurrence at 52, 29, and 21 months, serum CA 125 levels remained below 5 U/ml after remission. These results suggest that CA 125 is useful in monitoring patients with primary carcinoma of the fallopian tube.

[A case of lymphocytic adenohypophysitis associated with sarcoidosis of the lung and eye]

Lymphocytic adenohypophysitis is considered to be an inflammatory disease of the adenohypophysis that is commonly present with visual disturbance and hypopituitarism. Its etiology remains unclear but it is often related to an autoimmune disorder involving other organs, such as the thyroid, parathyroid, or adrenal glands. We encountered a rare case of lymphocytic adenohypophysitis associated with sarcoidosis of the lung and eye during the follow-up period. A 23-year-old woman was hospitalized in July 1986, with a one-month history of headache and visual disturbances which began three days after her second normal delivery. On admission, she showed slight visual impairment and had a left temporal superior quadrantanopia. Endocrinological evaluation revealed thyroid and adrenal hypofunction, and low response of human growth hormone to the loading test. A skull X-ray showed normal shaped sella with some erosion of the dorsum. CT scan showed a rounded contrast-enhanced intrasellar mass extending into the suprasellar cistern. MRI (SR: 500/30) showed a homogeneous low intensity mass which contained a small high intensity area on the relative T2-weighted image (2000/50). A biopsy was performed via right frontotemporal craniotomy. The consistency of the resected tissue was firmer than that of pituitary adenoma. Histologically, the tissue showed diffuse lymphocytic infiltration with some normal adenohypophysis. Her postoperative course was uneventful and the visual impairment improved two months later after the operation. Six months after the operation, she was readmitted with complaints of general fatigue and breathlessness. Chest X-ray showed diffuse infiltration throughout both lung fields, but there was no bilateral hilar lymphadenopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

A possible coupling of postjunctional ATP release and transmitters' receptor stimulation in smooth muscles

The nature of ATP release from mainly smooth muscles of guinea-pig was evaluated with KCl and agonists for different kinds of receptors. In ileal longitudinal muscles, amounts of net ATP release by ACh and bethanechol (1-10 microM) were much larger (about 10 fold) than that by other drugs, e.g., histamine, 5-hydroxytryptamine, prostaglandin-F2 alpha, substance P and bradykinin, including KC1, although differences between contractions of the tissue evoked by test drugs were approximately 1.5 times at most. The ATP release, as well as the contraction, evoked by ACh or bethanechol was markedly reduced by atropine (0.3 microM), thus, indicating primarily postjunctional release of ATP. The remarkable ATP release from vas deferens by norepinephrine (NE), but not by substance P, was abolished almost completely by prazosin (0.3 microM). Increases in intracellular Ca2+ and subsequent contraction in the ileal tissue were produced by ATP and these responses were fully antagonized by nifedipine (0.1 microM). These findings provide evidence that the drugs-stimulated ATP release from smooth muscles does not result from contractility of muscles, but is substantially elicited only by stimulation of neurotransmitter (NE or ACh) receptors, suggesting the existence of the receptor-stimulus-postjunctional ATP release coupling. The released ATP may contribute, in part, to the muscle contractility via increase of Ca2(+)-influx, presumably, in a manner related to the voltage-gated Ca2(+)-channels.