Reduced susceptibility to ischemic brain injury and N-methyl-D-aspartate-mediated neurotoxicity in cyclooxygenase-2-deficient mice

Cyclooxygenase-2 (COX-2), a prostanoid-synthesizing enzyme that contributes to the toxicity associated with inflammation, has recently emerged as a promising therapeutic target for several illnesses, ranging from osteoarthritis to Alzheimer's disease. Although COX-2 has also been linked to ischemic stroke, its role in the mechanisms of ischemic brain injury remains controversial. We demonstrate that COX-2-deficient mice have a significant reduction in the brain injury produced by occlusion of the middle cerebral artery. The protection can be attributed to attenuation of glutamate neurotoxicity, a critical factor in the initiation of ischemic brain injury, and to abrogation of the deleterious effects of postischemic inflammation, a process contributing to the secondary progression of the damage. Thus, COX-2 is involved in pathogenic events occurring in both the early and late stages of cerebral ischemia and may be a valuable therapeutic target for treatment of human stroke.

Structural abnormalities of great arterial walls in congenital heart disease: light and electron microscopic analyses

BACKGROUND

Great arteries in congenital heart disease (CHD) may dilate, become aneurysmal, or rupture. Little is known about medial abnormalities in these arterial walls. Accordingly, we studied 18 types of CHD in patients from neonates to older adults.

METHODS AND RESULTS

Intraoperative biopsies from ascending aorta, paracoarctation aorta, truncus arteriosus, and pulmonary trunk in 86 patients were supplemented by 16 necropsy specimens. The 102 patients were 3 weeks to 81 years old (average, 32+/-6 years). Biopsies were examined by light (LM) and electron (EM) microscopy; necropsy specimens by LM. Positive aortic controls were from 15 Marfan patients. Negative aortic controls were from 11 coronary artery disease patients and 1 transplant donor. Nine biopsies from acquired trileaflet aortic stenosis were compared with biopsies from bicuspid aortic stenosis. Negative pulmonary trunk controls were from 7 coronary artery disease patients. A grading system consisted of negative controls and grades 1, 2, and 3 (positive controls) based on LM and EM examination of medial constituents.

CONCLUSIONS

Medial abnormalities in ascending aorta, paracoarctation aorta, truncus arteriosus, and pulmonary trunk were prevalent in patients with a variety of forms of CHD encompassing a wide age range. Aortic abnormalities may predispose to dilatation, aneurysm, and rupture. Pulmonary trunk abnormalities may predispose to dilatation and aneurysm; hypertensive aneurysms may rupture. Pivotal questions are whether these abnormalities are inherent or acquired, whether CHD plays a causal or facilitating role, and whether genetic determinants are operative.

Efficient methods for the synthesis of [2-15N]guanosine and 2'-deoxy[2-15N]guanosine derivatives

The nucleophilic addition-elimination reaction of 2',3',5'-tri-O-acetyl-2-fluoro-O6-[2-(4-nitrophenyl)ethyl]inosine (8) with [15N]benzylamine in the presence of triethylamine afforded the N2-benzyl[2-15N]guanosine derivative (13) in a high yield, which was further converted into the N2-benzoyl[2-15N] guanosine derivative by treatment with ruthenium trichloride and tetrabutylammonium periodate. A similar sequence of reactions of 2',3',5'-tri-O-acetyl-2-fluoro-06-[2-(methylthio)ethyl]inosine (9) and the 6-chloro-2-fluoro-9-(beta-D-ribofuranosyl)-9H-purine derivative (11), which were respectively prepared from guanosine, with potassium [15N]phthalimide afforded the N2-phthaloyl [2-15N]guanosine derivative (15; 62%) and 9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-6-chloro-2-[15N]phthalimido-9H-purine (17; 64%), respectively. Compounds 15 and 17 were then efficiently converted into 2',3',5'-tri-O-acetyl [2-15N]guanosine. The corresponding 2'-deoxy derivatives (16 and 18) were also synthesized through similar procedures.

Immunoassay of the MRSA-related toxic protein, leukocidin, with scanning electrochemical microscopy

Scanning electrochemical microscopy (SECM) was applied to the immunoassay of leukocidin, which is a toxic protein produced by methicillin-resistant Staphylococcus aureus (MRSA), with the intention of developing and early diagnostic for MRSA infection. An antibody-chip for leukocidin was prepared by self-assembling of anti-leukocidin on a protein A-coated glass substrate. A sample solution containing leukocidin was spotted onto the antibody-chip, followed by labeling with horseradish peroxidase (HRP) via a sandwich method. The reduction current of the oxidized form of ferrocenylmethanol generated by the HRP reaction was monitored to view SECM images of the spot of captured leukocidin. The amplitude of reduction current depended on the concentrations of sample solutions used for making spots. This SECM-based immunoassay detects as low as 5.25 pg mL(-1) leukocidin.

FMLP-induced formation of F-actin in HL60 cells is dependent on PI3-K but not on intracellular Ca2+, PKC, ERK or p38 MAPK

OBJECTIVE AND DESIGN

To further understand the mechanisms of signal transduction pathways for the formation of F-actin (polymerization of actin) and the activation of NADPH oxidase in phagocytic cells, the effects of various inhibitors on them were studied.

MATERIALS AND METHODS

Differentiated HL60 cells were studied to examine their N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated formation of F-actin and activation of NADPH oxidase following treatment with various inhibitors. These included a protein kinase C (PKC) inhibitor (GF 109203X), a phosphatidylinositide 3 kinase (PI3-K) inhibitor (wortmannin), an extracellular response kinase (ERK) inhibitor (PD 98059), a p38 mitogen-activated protein kinase (MAPK) inhibitor (SB 203580) and an intracellular Ca2+ -chelator (BAPTA-AM).

RESULTS

The treatment with wortmannin suppressed the formation of F-actin, with less suppression of the activation of NADPH oxidase. BAPTA-AM and GF 109203X did not attenuate the formation of F-actin but completely inhibited the activation of NADPH oxidase. PD 98059 and SB 203580 partially inhibited the activation of NADPH oxidase without influence on the formation of F-actin. Furthermore, wortmannin but not BAPTA-AM and GF 109203X inhibited the fMLP-induced activation of Akt, which is known to regulate NADPH oxidase.

CONCLUSIONS

These results suggest that the formation of F-actin is dependent on PI3-K and independent of PKC, ERK and p38 MAPK as well as the increase in intracellular Ca2+, whereas the activation of NADPH oxidase is partly dependent on ERK, p38 MAPK, Akt regulated by PI3-K, and strongly dependent on the activation of PKC and the increase in intracellular Ca2+.

End-linked homodimers in fibrinogen Osaka VI with a B beta-chain extension lead to fragile clot structure

The authors have identified a 12-residue carboxyl-terminal extension of Lys-Ser-Pro-Met-Arg-Arg-Phe-Leu-Leu-Phe-Cys-Met in a dysfibrinogen derived from a woman heterozygotic for this abnormality and associated with severe bleeding. This extension is due to a T-to-A mutation that creates AAG encoding Lys at the stop (TAG) codon, thus translating 36 base pairs in the noncoding region of the Bbeta gene. The extra Cys residues appear to be involved in 1 or 2 disulfide bonds between 2 adjacent abnormal fibrinogen molecules, forming a fibrinogen homodimer as indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Indeed, about half of the fibrinogen molecules exist as end-linked dimers oriented in parallel or with an angle, as observed by transmission electron microscopy. These end-linked dimers may well alter the conformations of D and DD regions on fibrin assembly, leading to increased fiber branching at their sites in the growing protofibrils. By scanning electron microscopy, the Osaka VI fibrin network appears to have a lacelike structure composed of highly branched, thinner fibers than the normal fibrin architecture. Such fibrin networks may be easily damaged to form large pores when fluids are allowed to pass through the gels. The fragility of Osaka VI fibrin clots, further confirmed by permeation and compaction studies, may account for the massive bleeding observed in this patient. (Blood. 2000;96:3779-3785)

Exogenous A beta1-40 reproduces cerebrovascular alterations resulting from amyloid precursor protein overexpression in mice

Transgenic mice overexpressing the amyloid precursor protein (APP) have a profound impairment in endothelium-dependent cerebrovascular responses that is counteracted by the superoxide scavenger superoxide dismutase (SOD). The authors investigated whether the amyloid-beta peptide (A beta) is responsible for the cerebrovascular effects of APP overexpression. Cerebral blood flow (CBF) was monitored by a laser-Doppler flowmeter in anesthetized-ventilated mice equipped with a cranial window. Superfusion of A beta1-40 on the neocortex reduced resting CBF in a dose-dependent fashion (-29% +/- 7% at 5 micromol/L) and attenuated the increase in CBF produced by the endothelium-dependent vasodilators acetylcholine (-41% +/- 8%), bradykinin (-39% +/- 9%), and the calcium ionophore A23187 (-37% +/- 5%). A beta1-40 did not influence the CBF increases produced by the endothelium-independent vasodilators S-nitroso-N-acetylpenicillamine and hypercapnia. In contrast, A beta1-42 did not attenuate resting CBF or the CBF increases produced by endothelium-dependent vasodilators. Cerebrovascular effects of A beta1-40 were reversed by the superoxide scavengers SOD or MnTBAP. Furthermore, substitution of methionine 35 with norleucine, a mutation that blocks the ability of A beta to generate reactive oxygen species, abolished A beta1-40 vasoactivity. The authors conclude that A beta1-40, but not A beta1-42, reproduces the cerebrovascular alterations observed in APP transgenics. Thus, A beta1-40 could play a role in the cerebrovascular alterations observed in Alzheimer's dementia.

Preventive effects of danazol on endometrial carcinogenesis in mice

Short and long-term experiments were designed to determine effects of danazol on estrogen-related endometrial carcinogenesis in mice. The short-term assays showed that danazol decreased expression levels of c-fos/jun mRNA and their oncoproteins induced by estradiol-17beta (E2). For the long-term assay, 85 female ICR mice were given N-methyl-N-nitrsourea solution into their uterine corpora. The animals were divided into three groups as follows: Group 1, E2-diet (5 ppm) plus danazol (2 mg/body (s.c.), every 4 weeks); Group 2, E2-diet alone, Group 3, basal diet alone. At 30 weeks, incidences of atypical and complex endometrial hyperplasia were significantly decreased by danazol-treatment. These results suggest that danazol has preventive effects on estrogen-related endometrial carcinogenesis in mice, through the suppression of estrogen-induced c-fos/jun-expression.

Synergistic effects of danazol and mifepristone on the cytotoxicity of UCN-01 in hormone-responsive breast cancer cells

BACKGROUND

7-Hydroxystaurosporine (UCN-01) is a novel antitumor agent as well as a potent inhibitor of a variety of protein kinases with a preference to protein kinase C. Because an intimate interaction exists between PKC signaling and the ER signaling pathways, sex steroid agonists/antagonists might modulate the cytotoxicity of UCN-01.

MATERIALS AND METHODS

Effects of sex steroid agonists and antagonists on the UCN-01 cytotoxicity were analyzed by MTT assay in MCF-7/WT and MCF-7/ADR, a multiple drug resistance phenotype lacking ER and PR.

RESULTS

MCF-7/ADR is 23-fold more resistant to UCN-01 than MCF-7. In MCF-7/WT, danazol and mifepristone enhanced the cytotoxicity of UCN-01, while these agents did not exert any significant effects on it in MCF-7/ADR.

CONCLUSION

These results suggest that danazol or mifepristone might enhance the antitumor activity of UCN-01 in hormone-dependent cancer cells by interacting with PR.

Leiomyoma of the fallopian tube

Leiomyomas of the fallopian tube are rare. They are typically incidental findings seen at autopsy or unrelated surgical procedures. A 32-year-old woman presented with lower abdominal pain and mass. Transvaginal sonogram and magnetic resonance imaging showed the solid mass at the outside of the uterus. At surgery, the left fallopian tube contained a firm mass with torsion in the area of the ampullary-isthmic junction. The left tube and the infundibulopelvic ligament were rolled in torsion and showed edematous change. We report a rare case in whom torsion of a pedunculated tubal leiomyoma caused abdominal pain.

Abeta 1-40-related reduction in functional hyperemia in mouse neocortex during somatosensory activation

Peptides derived from proteolytic processing of the beta-amyloid precursor protein (APP), including the amyloid-beta peptide (Abeta), play a critical role in the pathogenesis of Alzheimer's dementia. We report that transgenic mice overexpressing APP and Abeta have a profound attenuation in the increase in neocortical blood flow elicited by somatosensory activation. The impairment is highly correlated with brain Abeta concentration and is reproduced in normal mice by topical neocortical application of exogenous Abeta1-40 but not Abeta1-42. Overexpression of M146L mutant presenilin-1 in APP mice enhances the production of Abeta1-42 severalfold, but it does not produce a commensurate attenuation of the hyperemic response. APP and Abeta overexpression do not diminish the intensity of neural activation, as reflected by the increase in somatosensory cortex glucose usage. Thus, Abeta-induced alterations in functional hyperemia produce a potentially deleterious mismatch between substrate delivery and energy demands imposed by neural activity.

The paternal methylation imprint of the mouse H19 locus is acquired in the gonocyte stage during foetal testis development

BACKGROUND

Germline-specific differential DNA methylation that persists through fertilization and embryonic development is thought to be the 'imprint' distinguishing the parental alleles of imprinted genes. If such methylation is to work as the imprinting mechanism, however, it has to be reprogrammed following each passage through the germline. Previous studies on maternally methylated genes have shown that their methylation imprints are first erased in primordial germ cells (PGCs) and then re-established during oocyte growth.

RESULTS

We have examined the timing of the reprogramming of the paternal methylation imprint of the mouse H19 gene during germ cell development. In both male and female PGCs, the paternal allele is partially methylated whereas the maternal allele is unmethylated. This partial methylation is completely erased in the female germline by entry into meiosis, establishing the oocyte methylation pattern. In the male germline, both alleles become methylated, mainly during the gonocyte stage, establishing the sperm methylation pattern.

CONCLUSION

The paternal methylation imprint of H19 is established in the male germline and erased in the female germline at specific developmental stages. The identification of the timings of the methylation and demethylation should help to identify and characterize the biochemical basis of the reprogramming of imprinting.

An efficient method for the synthesis of [2-(15)N]guanosine and 2'-deoxy[2-(15)N]guanosine derivatives

Nucleophilic substitution reaction of 6-chloro-2-fluoro-9-beta-D-ribofuranosyl-9H-purine derivative, prepared from guanosine, with potassium [15N]phthalimide at 40 degrees C for 9 h in DMF, followed by hydrolysis, afforded [2-(15)N]guanosine derivative efficiently. The corresponding 2'-deoxy derivative was also synthesized through a similar procedure.

Expression of PTEN and PTEN pseudogene in endometrial carcinoma

PTEN is a tumor suppressor gene and its mutation is frequently found in endometrial carcinoma. Recently, the pseudogene of PTEN has been reported to be actively transcribed in a number of cells and tissues and a potential for translation is suggested. For further understanding of the involvement of PTEN in endometrial carcinogenesis, we analysed the expressions of PTEN and the pseudogene in 36 endometrial carcinomas with special reference to the genetic status of PTEN. Mutations of PTEN were found in 42% (15/36) of the endometrial carcinomas. The transcript of the pseudogene was expressed in 6 samples (17%) of 36 endometrial carcinomas, but in none of the normal endometria. Western blot analysis showed no translated protein of the pseudogene in any of the cases. Steady level of PTEN protein expression was observed in all the cases examined. Expression level was consistent among the proliferative endometria, secretory endometria and endometrial carcinomas as long as PTEN protein was not truncated. These results indicate that PTEN is a constitutive protein in the endometrium, so that the somatic mutation of PTEN exerts a crucial effect on the endometrial carcinogenesis. In addition, the presence of the PTEN pseudogene transcript urges us caution for the mutational analysis of PTEN as well as careful choice of the probe for the detection of PTEN transcript.

The 5'-end of hTERT mRNA is a good target for hammerhead ribozyme to suppress telomerase activity

Because the expression level of hTERT, a catalytic subunit of human telomerase, is a rate-limiting determinant of telomerase activity, hTERT mRNA would be an excellent target of hammerhead ribozymes for the regulation of telomerase activity. We studied the efficiency of several hammerhead ribozymes targeting hTERT mRNA by transient and stable transfection procedures. To screen the potency of the ribozymes, transient ribozyme transfection and telomerase determination were performed. The ribozyme targeting 13 nucleotides downstream from the 5'-end of hTERT mRNA (13-ribozyme) exhibited the strongest telomerase-inhibitory activity, and the ribozyme to target 59 nucleotides upstream from the poly(A) tail showed clear activity. A stable transfection study confirmed that the 13-ribozyme suppressed telomerase. These observations suggest that the 13-ribozyme can regulate telomerase activity and may possess potential for cancer therapy.

Comparison of the efficacy of two air-based contrast agents in dogs

OBJECTIVE

The aim of this study was to evaluate the differences of the in vivo efficacies of Levovist(SH U 508 A) and Albunex, air-based contrast agents (CAs) with different shell materials, by direct comparison.

METHODS

SH U 508 A, 300 mg/ml, and Albunex were injected intravenously at doses of 0.1 and 0.15 ml/kg, respectively, into the same dogs (n=6). Contrast enhancement in the left ventricle was evaluated visually and by off-line measurement of brightness.

RESULTS

Both CAs yielded good peak contrast, while the duration of contrast enhancement with SH U 508 A was seven times that with Albunex. With Albunex, reduction of contrast enhancement at end-systole and in the late phase of diastole during one heartbeat was observed, and a positive correlation was observed between contrast enhancement and heart rate. Contrast enhancement was nearly constant during one heartbeat with SH U 508 A.

CONCLUSION

SH U 508 A yielded consistent and longer contrast enhancement in the left ventricle than Albunex under the same conditions.

Postoperative vesicourethral function after ultrasonic surgical aspirator-assisted surgery of gynecologic malignancies

OBJECTIVE

The most concerned complication of radical hysterectomy includes the vesicourethral dysfunction. The use of Cavitron ultrasonic surgical aspirator (CUSA) may preserve the blood supply to the urinary tract even during the surgical procedure, prompting us to evaluate the advantage of using the CUSA with the complication.

STUDY DESIGN

We analyzed medical profiles of a total of 275 patients with pelvic lymphnode dissection (137 subjects with radical hysterectomy and 138 with modified radical hysterectomy).

RESULTS

The use of CUSA in radical (formal or extended) hysterectomy reduced the period for the residual urine to become <50 ml in cases of advanced stages equal and over Ib of uterine cervical cancers.

CONCLUSION

The CUSA may be more effective in the prevention of radical hysterectomy for its major complication, vesicourethral dysfunction. The CUSA-assisted surgery may be applicable, primarily, for advanced uterine cancer.

Expression of GFP in Nuclear Transplants Generated by Transplantation of Embryonic Cell Nuclei from GFP-Transgenic Fish into Nonenucleated Eggs of Medaka,Oryzias latipes

In order to investigate whether foreign genes can be used as genetic markers of donor nuclei in fish nuclear transplantation, expression of the GFP gene derived from donor nuclei was examined in nuclear transplants in medaka (Oryzias latipes). Embryonic nuclei were obtained from blastula embryos produced by crossing of transgenic fish of the wild-type strain heterozygous for the GFP gene with nontransgenic ones or by mutual crossing between transgenic fish. The GFP gene was driven by the promoter of the medaka elongation factor gene, EF-1alpha-A, which is known to induce GFP expression in many tissues except for the muscle in the transgenic fish. The nuclei were transplanted into nonenucleated unfertilized eggs of the orange-red strain. Adult nuclear transplants were successfully obtained at the rate of about 2% of the operated eggs. They were triploid and had no reproductive potential. The GFP gene was expressed in embryos, fry, and adults of nuclear transplants in a pattern similar to that in the transgenic fish. These results indicate that GFP is useful as a foreign genetic marker of donor nuclei in fish nuclear transplantation.

Expression of tumor necrosis factor-alpha protein in the myocardium in fatal myocarditis

BACKGROUND

Tumor necrosis factor (TNF)-alpha is the most studied cytokine in the failing human heart and in experimental murine myocarditis. We have investigated the expression of TNF-alpha in the myocardium in human myocarditis.

METHODS

We examined endomyocardial biopsy (n = 4) and autopsy (n = 5) tissues obtained from nine patients diagnosed with myocarditis by the Dallas criteria. Expression of TNF-alpha in the hearts was immunohistochemically studied using monoclonal antibodies against human TNF-alpha.

RESULTS

Tumor necrosis factor-alpha protein was expressed in the myocardium of six of the nine patients studied. Four of five fatal patients showed intense immunoreactivity for TNF-alpha compared with survivors. Furthermore, left ventricular systolic function was reduced in patients with TNF-alpha-positive hearts.

CONCLUSIONS

These findings may support the suggestion that TNF-alpha plays an important role in cardiac dysfunction and myocytic damage in fatal human myocarditis.

Cyclooxygenase-2 contributes to functional hyperemia in whisker-barrel cortex

The prostanoid-synthesizing enzyme cyclooxygenase-2 (COX-2) is expressed in selected cerebral cortical neurons and is involved in synaptic signaling. We sought to determine whether COX-2 participates in the increase in cerebral blood flow produced by synaptic activity in the somatosensory cortex. In anesthetized mice, the vibrissae were stimulated mechanically, and cerebral blood flow was recorded in the contralateral somatosensory cortex by a laser-Doppler probe. We found that the COX-2 inhibitor NS-398 attenuates the increase in somatosensory cortex blood flow produced by vibrissal stimulation. Furthermore, the flow response was impaired in mice lacking the COX-2 gene, whereas the associated increase in whisker-barrel cortex glucose use was not affected. The increases in cerebral blood flow produced by hypercapnia, acetylcholine, or bradykinin were not attenuated by NS-398, nor did they differ between wild-type and COX-2 null mice. The findings provide evidence for a previously unrecognized role of COX-2 in the mechanisms coupling synaptic activity to neocortical blood flow and provide an insight into one of the functions of constitutive COX-2 in the CNS.

A case-control study of uterine endometrial cancer of pre- and post-menopausal women

Endometrial cancers are generally divided into at least two different pathogenetic types. One occurs from the proliferative endometrium, depending on continuous estrogen stimulation, while the other is not related to the stimulation and occurs from the atrophic endometrium of older post-menopausal women. In order to assess the risk factors for endometrial carcinoma (EC), a case-control study with 136 Japanese women having EC and with 376 healthy controls for ECs in Japan, together with an immunohistochemical analyses on p53, estrogen (ER) and progesterone receptors (PR) of EC patients was undertaken. Nulliparity, increased BMI, hypertension, diabetes mellitus, later age at menopause and personal cancer history were all seen predominantly in the EC group. Frequency of irregular menses, polycystic ovary syndrome (PCOS) and obesity in the EC patients under 40-year old was significantly higher than the control group. Immunohistochemical expressions of ER (P<0.05) and PR (P<0. 01) were more frequently recognized in the EC of the pre-menopausal than in the post-menopausal patients. On the other hand, p53 overexpression was detected in 27.2% of the post-menopausal EC group, while only found in 7.1% of the pre-menopausal EC group. These findings indicate that possible factors related to endometrial carcinogenesis are different between the pre- and post-menopausal EC patients. Namely, untreated ovarian dysfunction such as PCOS with unopposed estrogenic action in the endometrium may be associated with development and growth of EC in younger women, yet abnormality of p53 gene may be more concerned with the development of the post-menopausal EC, independently of sex steroid influence.

Both fertilization promoting peptide and adenosine stimulate capacitation but inhibit spontaneous acrosome loss in ejaculated boar spermatozoa in vitro

Both fertilization promoting peptide (FPP) and adenosine stimulate capacitation and inhibit spontaneous acrosome loss in epididymal mouse spermatozoa; these responses involve modulation of the adenylyl cyclase (AC)/cAMP signal transduction pathway. However, it was unclear whether these responses were restricted to the mouse or possibly common to many mammalian species. To address this question, the response of boar spermatozoa to FPP and/or adenosine was evaluated. FPP is found in nanomolar concentrations in seminal plasma of several mammals, but not the pig. When cultured in caffeine-containing Medium 199 for 2 hr, chlortetracycline fluorescence evaluation indicated that neither FPP nor adenosine stimulated boar sperm capacitation per se but did inhibit spontaneous acrosome loss. However, in caffeine-free medium, FPP and adenosine both stimulated capacitation and inhibited spontaneous acrosome loss, suggesting that boar spermatozoa have receptors for both FPP and adenosine. Gln-FPP, a competitive inhibitor of FPP in mouse spermatozoa, has recently been shown to inhibit mouse sperm responses to adenosine as well, suggesting that FPP receptors and adenosine receptors interact in some way. Used with boar spermatozoa, Gln-FPP also significantly inhibited responses to both FPP and adenosine. These responses suggest that mechanisms whereby FPP and adenosine can regulate sperm function, via AC/cAMP, are of considerable physiological significance. Mouse, human, and now boar spermatozoa have been shown to respond to FPP, suggesting that these mechanisms may be common to many mammalian species. We also suggest that the effects of FPP and adenosine could also be exploited to maximize monospermic fertilization in porcine in vitro fertilization.