Stimulation of Ca efflux by N-formyl chemotactic peptides in guinea-pig peritoneal macrophages

Effects of N-formyl chemotactic peptides on the Ca²⁺ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of ⁴⁵Ca²⁺ into macrophages, whereas it stimulated the efflux of ⁴⁵Ca²⁺ from macrophages at concentrations ranging from 10⁻¹⁰ M to 10⁻⁷ M. fMet-Met-Met and fMet-Leu also stimulated the ⁴⁵Ca²⁺ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN₃, did not modify the ⁴⁵Ca²⁺ efflux induced by the chemoattractants, yet they did induce the release of ⁴⁵Ca²⁺ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of ⁴⁵Ca²⁺ from the NaN₃-insensitive Ca²⁺ store site and mimicked the enhancement of the ⁴⁵Ca²⁺ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca²⁺ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca²⁺ from the NaN₃-insensitive Ca²⁺ store site.     

Stimulation of Ca2+ efflux by N-formyl chemotactic peptides in guinea-pig peritoneal macrophages

Effects of N-formyl chemotactic peptides on the Ca²⁺ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of ⁴⁵Ca²⁺ into macrophages, whereas it stimulated the efflux of ⁴⁵Ca²⁺ from macrophages at concentrations ranging from 10^?10 M to 10^?7 M. fMet-Met-Met and fMet-Leu also stimulated the ⁴⁵Ca²⁺ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN₃, did not modify the ⁴⁵Ca²⁺ efflux induced by the chemoattractants, yet they did induce the release of ⁴⁵Ca²⁺ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of ⁴⁵Ca²⁺ from the NaN₃-insensitive Ca²⁺ store site and mimicked the enhancement of the ⁴⁵Ca²⁺ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca²⁺ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca²⁺ from the NaN₃-insensitive Ca²⁺ store site.     

Focal Stimulation of the Mossy Fibers Releases Endogenous Dynorphins That Bind K1-Opioid Receptors in Guinea Pig Hippocampus

Physiological release of endogenous opioids in guinea pig hippocampal slices was detected in an in vitro competition binding assay using [3H]U69,593, a kappa 1-selective radioligand. Veratridine-induced opioid release caused a decrease in [3H]U69,593 binding that was blocked by either tetrodotoxin addition or the removal of calcium from the incubation buffer. Focal electrical stimulation of opioid peptide-containing afferent pathways resulted in a decrease in [3H]U69,593 binding, whereas stimulation of a major afferent lacking endogenous opioid immunoreactivity had no effect. The addition of 6-cyano-7-nitroquinoxaline-2,3-dione blocked the reduction in [3H]U69,593 binding caused by perforant path stimulation, but not the reduction caused by mossy fiber stimulation, suggesting that the primary source of endogenous kappa ligands was likely to be the dentate granule cells. Antisera against dynorphin A(1-8) or dynorphin B peptides inhibited the effects of mossy fiber stimulation in the [3H]U69,593 displacement assay. Antisera against other prodynorphin- and proenkephalin-derived opioid peptides had no effect. As shown by receptor autoradiography, the distribution of kappa 1 binding sites was limited to the molecular layer of the dentate gyrus and the presubiculum region of temporal hippocampal slices. These results indicate that prodynorphin-derived opioids released under physiological conditions from the mossy fibers act at kappa 1 receptors in the guinea pig dentate gyrus.     

Existence of Three Subtypes of Bradykinin B2 Receptors in Guinea Pig

We describe the binding of [3H]bradykinin to homogenates of guinea pig brain, lung, and ileum. Analysis of [3H]bradykinin binding kinetics in guinea pig brain, lung, and ileum suggests the existence of two binding sites in each tissue. The finding of two binding sites for [3H]bradykinin in ileum, lung, and brain was further supported by Scatchard analysis of equilibrium binding in each tissue. [3H]Bradykinin binds to a high-affinity site in brain, lung, and ileum (KD = 70-200 pM), which constitutes approximately 20% of the bradykinin binding, and to a second, lower-affinity site (0.63-0.95 nM), which constitutes the remaining 80% of binding. Displacement studies with various bradykinin analogues led us to subdivide the high- and lower-affinity sites in each tissue and to suggest the existence of three subtypes of B2 receptors in the guinea pig, which we classify as B2a, B2b, and B2c. Binding of [3H]bradykinin is largely to a B2b receptor subtype, which constitutes the majority of binding in brain, lung, and ileum and represents the lower-affinity site in our binding studies. Receptor subtype B2c constitutes approximately 20% of binding sites in the brain and lung and is equivalent to the high-affinity site in brain and lung. We suggest that a third subtype of B2 receptor (high-affinity site in ileum), B2a, is found only in the ileum. All three subtypes of B2 receptors display a high affinity for bradykinin, whereas they show different affinities for various bradykinin analogues displaying agonist or antagonist activities.(ABSTRACT TRUNCATED AT 250 WORDS)     

A multivariate approach to fingerprint variation in Papua New Guinea: Perspectives on the evolutionary stability of dermatoglyphic markers

In the Markham Valley of Papua New Guinea, multivariate graphical displays of serological, anthropometric, and dermatoglyphic population structures are compared pursuant to the hypothesis that fingerprints have a slower velocity of evolutionary change and, therefore, are preferable biological markers for prehistorical reconstructions. Samples from nine villages, which represent three geographical and linguistic populations, are plotted in two dimensions using appropriate multivariate techniques for maximally portraying between sample variability. Both the serological and morphometric displays are found lacking in close clusters, which demonstrates a lack of congruence with the shared languages and, presumably, the ethnohistorical origins of the three populations. These discrepancies between biology and prehistory appear to reflect recent environmental and stochastic perturbations. On the other hand, fingerprint displays conform closely to language affiliations, relatively undisturbed by environmental variation and genetic drift. The relative congruence between ethnohistorical affiliation and fingerprint diversity is further corroborated by comparing the three measures of population structure with geographical distances, using partial rank correlations. In terms of explained variance, the level of association with fingerprints is more than twice than with anthropometry, and 13 times greater than with serology. Whereas metric and serological data provide distorted portrayals of known biohistorical relationships among the study populations, fingerprint data mirror these relationships. The theoretical foundations and consequences of this observation are discussed with respect to the broader question of polygenic versus monogenic biological markers.     

Ixodes dammini: Induced skin lesions in guinea pigs and rabbits compared to erythema chronicum migrans in patients with lyme arthritis

Erythematous skin lesions occurred in rabbits 2 days after being fed upon by larvae or nymphs of the tick, Ixodes dammini. Similar lesions occurred in guinea pigs 7 days after a primary infestation with either larvae or nymphs. Host resistance to secondary feeding by larvae was demonstrated in guinea pigs and rabbits. Host resistance to secondary feeding by nymphs was seen in guinea pigs, but not in rabbits. Guinea pigs developed resistance to nymphs after being previously fed upon twice by larvae. All skin lesions in resistant guinea pigs contained large accumulations of basophils (49–76% of cells) with smaller (20–33%), but significant, numbers of eosinophils. These responses were characteristic of strong cutaneous basophil hypersensitivity reactions. Primary and secondary lesions in rabbits fed upon by larvae contained mostly mononuclear cells (46–52%) and moderate numbers (16–30%) of basophils and eosinophils. Primary and secondary lesions in rabbits fed upon by nymphs had few (3–11%) basophils and eosinophils and were dominated by mononuclear cells (73–86%). Thus, acquired resistance in guinea pigs and rabbits was associated with cutaneous basophil and eosinophil responses and the lack of resistance of rabbits to nymphs was associated with erythematous lesions dominated by mononuclear cells. The mononuclear nature of rabbit lesions induced by nymphal feeding was similar to that seen in erythema chronicum migrans in Lyme arthritis patients who are thought to have been fed upon by I. dammini nymphs. This study confirms the cutaneous basophil hypersensitivity characteristics of lesions in guinea pigs resistant to ticks and demonstrates a relationship between the mononuclear cell response of rabbits to nymphal I. dammini and the cellular response seen in patients with erythema chronicum migrans and Lyme arthritis.     

Adenosine Transport into Guinea-pig Synaptosomes

Abstract: Kinetics for transport of adenosine into guinea-pig neocortex synaptosomes were studied by incubating them with [¹⁴C]adenosine for up to 30 s. The apparent K _m value of the high-affinity transport system for adenosine was 21.1 μM and the V _max value was 257.3 pmol/min/mg protein. The transport system was inhibited by both compounds structurally related (compounds 554 and 555) and unrelated (dipyridamole) to adenosine. Because electrically stimulated synaptosomes release up to 1.5% of the adenosine derivative content per min, the physiological significance of adenosine uptake is discussed as a possible mechanism to compensate for the loss of adenine nucleotides from synaptosomes preparations.     

Evidence for a nervous connection between the brain and the pineal organ in the guinea pig

Summary Following the injection of horseradish peroxidase into the pineal organ of the guinea pig, approximately 30 nerve fibers were demonstrated in the pineal stalk due to the retrograde transport of the tracer enzyme in these elements. Finely branched extensions of these nerve fibers are directed toward the distal portion of the pineal organ. This projection of central nervous elements enters the pineal organ via the habenular or posterior commissures. Neuronal perikarya projecting into the pineal organ are found in the region of the paraventricular nucleus near the border of the third ventricle.In partial fulfillment of the requirements for the degree of Dr. med., Faculty of Medicine, Justus Liebig University of Giessen     

Immuno-electron microscopic identification of somatostatin in cells and axons of sympathetic ganglia in the guinea pig

Summary The superior cervical ganglia (SCG), celiac superior mesenteric ganglia (CMG), and splanchnic nerve of unoperated guinea pigs, as well as both proximal and distal stumps of a previously transected branch of the postganglionic plexus of the CMG, were immunostained for somatostatin (SS). In addition, the PAP technique was adapted for fine-structural visualization of SS. A greater proportion of cells were labeled for SS in the CMG than in the SCG. PAP molecules were present in one type of intraganglionic axons. Only two labeled axons were found in the splanchnic nerve. Neither proximal nor the distal stump of the transected CMG postganglionic nerve contained labeled axons. The present results support the hypothesis that the intraganglionic axons labeled for SS arise from SS-containing intraganglionic neurons.     

Angiostrongylus cantonensis: Rejection of pulmonary arterial transfers of lung stage worms

Experimental transfer of the lung stage worms of Angiostrongylus cantonensis was performed between permissive hosts (rats) and between permissive (rat) and nonpermissive hosts (guinea pigs and rabbits). These worms from rats were rejected when implanted into nonpermissive hosts. Unexpectedly, similar worms did not survive well even in permissive hosts; the majority of recipient rats did not have first-stage larvae (L₁) in their stools and, even when positive for L₁, the number of the larvae shed was few. These findings contrast with the successful pulmonary arterial transfer of younger, intracranial-stage worms. It was shown that differences in rat strain between donor and recipient had no significant effect on the subsequent worm survival in recipient hosts. The alteration of maintaining conditions of the intrapulmonary worms, prior to transfer, in terms of temperature, media, and maintaining period, also showed no profound effect on the subsequent worm survival. The kinetics of precipitating and reaginic antibody levels in rats implanted with the intrapulmonary worms were analogous to those in rats with intracranial-stage worms. The findings indicate that some qualitative differences may exist between the worms obtained from two different sites.