Influence of gender on the diurnal variation of urine production and micturition characteristics of the rat.

The diurnal variation in the frequency/volume characteristics of male and female conscious rats was evaluated with reference to fluid consumption and urine production. Baseline values of the micturition volume and frequency of nine male and 10 female SD adult rats were measured over a 24-hour time period. The level of initial hydration conditions was standardized with 5 ml of water administered orally. With animals in a metabolism chamber having free access to water, the total volume of water consumed, the frequency/volume characteristics during micturition and the urine production rate were derived from the measurements of voided volume as detected by a digital balance. To establish reliability of measurements two separate micturition studies were done per rat at an interval of 1 week. Mean frequency of micturition and mean volume voided per micturition and urine production rate were computed in 3-hour time bins and represented over the 24-hour period. In addition the mean values of the number of micturitions and mean micturated volumes during the day/dark cycle were evaluated. The results show significant gender specificity in water consumption, urine production, and diurnal variations in micturition frequency/volume characteristics. Females consistently consume significantly larger amounts of water (83%) than males while urine production rate was correspondingly higher in females. It is concluded that water consumption and urine production are gender-specific. Because higher volumes of water are imbibed by females than males, the frequency/volume characteristic of micturition in the rat is also gender-specific. Data suggest that the volume voided per micturition depends on the urine production rate.

N-methyl-D-aspartate (NMDA) and opioid receptors mediate dynorphin-induced spinal cord injury: behavioral and histological studies.

Both N-methyl-D-aspartate (NMDA) and opioid receptors have been implicated in the pathophysiology of traumatic spinal cord injury and dynorphin-induced paralysis. The present studies compared the effects of the non-competitive NMDA antagonist dextrorphan (Dex) and the kappa-selective opioid antagonist nor-binaltorphimine (nor-BNI) on the acute motor deficits and chronic neuropathological alterations caused by intrathecally administered dynorphin A-(1-17) (Dyn A). Infusion of Dyn A into the rat lower thoracic spinal subarachnoid space produced acute, reversible hindlimb paresis. Histological evaluations of spinal cord sections from these animals at 2 weeks post-infusion revealed ventral grey matter necrosis, neuronal loss and gliosis as well as axonal loss in adjacent white matter; however, there was minimal alteration in serotonin immunocytochemistry caudal to the injury zone. Dex or non-BNI pretreatment each significantly (P less than 0.05) reduced, and to a similar degree, the acute motor deficits and certain histological changes associated with Dyn A administration. These findings further support the hypothesis that dynorphin-induced spinal cord injury involves both NMDA receptors and opioid receptors.

Hematologic interactions of endotoxin, tumor necrosis factor alpha (TNF alpha), interleukin 1, and adrenal hormones and the hematologic effects of TNF alpha in Corynebacterium parvum-primed rats.

Endotoxin reduces the release among other cytokines of tumor necrosis factor (TNF) and interleukin 1 (IL-1) and causes peripheral lymphopenia and a dose-response-dependent initial neutropenia followed by a monophasic neutrophilia. TNF alone induces lymphopenia and an initial neutropenia followed by a biphasic neutrophilia. IL-1 alone induces lymphopenia and a monophasic neutrophilia. TNF-plus-IL-1 caused a greater lymphopenia than either monokine alone, suggesting that both monokines contribute to LPS-induced lymphopenia. TNF-plus-IL-1 induced neutropenia similar in magnitude to that induced by TNF alone and induced a neutrophilia significantly greater than that induced by either monokine alone, suggesting that LPS-induced neutropenia is caused by TNF, while LPS-induced neutrophilia is due to the combined effects of TNF and II-1. TNF and IL-1 were administered together with LPS to simulate the in vivo condition of endogenous monokine release during gram-negative bacteremia. TNF combined with LPS increased both the duration and magnitude of LPS-induced lymphopenia, LPS-induced neutropenia, and LPS-induced neutrophilia. TNF-plus-LPS treated rats at 2 hours after injection exhibited a striking 93% decrease in bone marrow neutrophils even though no peripheral neutrophilia was yet apparent, suggesting that the subsequent neutrophilia was due to demargination and recirculation of neutrophils sequestered in the peripheral vasculature immediately after their release from the bone marrow. Epinephrine, which causes neutrophilia by demargination but not by release of marrow neutrophils, reversed the initial neutropenia in TNF-plus-LPS-treated rats and increased the neutrophilia. IL-1 combined with LPS increased LPS-induced neutrophilia, suggesting that endogenous IL-1 also contributed to LPS-induced neutrophilia. Corynebacterium parvum-primed rats with hyperplasia of the monocyte-macrophage system and treated with TNF differed from naive rats treated with TNF in that the second peak was as great as the initial peak of neutrophilia, supporting the hypothesis that the second peak of TNF-induced neutrophilia is due to the release of endogenous monokines. In conclusion, exogenous TNF, IL-1, and adrenal hormones affect circulating numbers of lymphocytes and neutrophils in a fashion consistent with their postulated endogenous role in the regulation of leukocyte trafficking during bacterial infection.

Mechanisms of tumor necrosis factor alpha-induced lymphopenia, neutropenia, and biphasic neutrophilia: a study of lymphocyte recirculation and hematologic interactions of TNF alpha with endogenous mediators of leukocyte trafficking.

Tumor necrosis factor alpha (TNF) induces lymphopenia, neutropenia, and biphasic neutrophilia after intravenous injection of 3,000 U TNF in Lewis rats. The mechanism of TNF-induced lymphopenia was investigated by means of thoracic duct cannulation. Hourly measurements of lymphocyte recirculation via the thoracic duct failed to reveal any significant decrease in lymphocyte recirculation in TNF-treated vs. control rats, suggesting that a decrease in lymphocyte recirculation through the thoracic duct is not the mechanism for TNF-induced lymphopenia. The mechanism of TNF-induced neutropenia was investigated by administering TNF to rats in whom a neutrophilia had been induced with interleukin-1 (IL-1). In rats with neutrophilia, TNF resulted in a sharp decrease in the circulating neutrophil pool, demonstrating that TNF induces neutropenia by causing neutrophils to leave the circulating pool rather than decreasing neutrophil release from the marrow. The mechanism of neutropenia was furthermore shown to be due to the transient intravascular margination of neutrophils by administering epinephrine concomitantly with TNF. Epinephrine, which causes neutrophilia solely by demargination, abrogated the TNF-induced neutropenia and actually resulted in a neutrophilia that was greater than the neutrophilia occurring in epinephrine alone-treated rats, demonstrating both that TNF had already caused release of marrow neutrophils at the time of peripheral neutropenia, and that the paradoxical neutropenia was due to the transient intravascular margination of neutrophils. The known property of epinephrine to cause neutrophilia exclusively by demargination was proved by examination of the bone marrow of epinephrine-treated rats in whom no decrease in marrow neutrophils was observed (in contrast to TNF- and IL-1-treated rats in whom neutrophilia is accompanied by a depletion of marrow neutrophils). The mechanism of TNF-induced neutrophilia was investigated by modulating the magnitude of both the first and second peaks of neutrophilia by priming of rats with daily injections of IFN gamma for 2 days prior to administration of TNF. The first peak of neutrophilia in IFN gamma-primed TNF-treated rats was decreased in comparison to TNF alone-treated rats because of the well-known neutropenic and myelosuppressive effect of IFN gamma, which resulted in a decrease in the number of neutrophils that could be recruited to cause neutrophilia.(ABSTRACT TRUNCATED AT 400 WORDS)

The development of humoral immunity to tissue-specific tubular basement membrane alloantigens after renal transplantation across the major histocompatibility barrier in rats immunomodulated with blood transfusions and cyclosporin.

The development of a humoral immune response to the tubular basement membrane (TBM) alloantigen of Brown-Norway (BN) rat kidneys was studied after transplantation of BN rat kidneys into bilaterally nephrectomized Lewis (LEW) rats. The LEW rat recipients consisted of four groups receiving no form of immunosuppression, pretransplantation cyclosporin alone, or pretransplantation donor-specific or donor-nonspecific transfusions combined with cyclosporin. The latter two regimens induce indefinite allograft survival in the majority of recipients. Circulating antibody to collagenase-solubilized BN rat renal basement membrane (CS-BN-RBM) was present in all four groups of transplant recipients within 1 week after transplantation, and no significant differences in antibody levels were noted between rats receiving no immunosuppression (survival of 1-2 weeks) and the groups of rats who received various immunosuppressive regimens and survived longer. Circulating antibody to BN-CS-RBM continued to increase in quantity in the cyclosporin-treated group until the time of death (2-10 weeks post-transplantation). In the much longer lived combined transfusion and cyclosporin-treated groups, circulating antibody to BN-CS-RBM generally attained a maximum at approximately 2 to 4 months post-transplantation and then plateaued or decreased somewhat before the time of death (3-16 months post-transplantation). No correlation was found between quantity of circulating anti-BN-CS-RBM antibody and post-transplantation survival. Comparative study of the quantity of circulating antibody to BN-CS-RBM (the presumed nephritogenic antigen of experimental tubulointerstitial nephritis in the BN rat) in serum from transplant recipients as compared to serum from BN rats with severe experimental tubulointerstitial nephritis (TIN) (as induced by immunization with heterologous TBM antigens) demonstrated a greater quantity of potentially nephritogenic antibody circulating in transplant recipients than in BN rats with experimental TIN. Histologically, the transplanted kidneys in immunomodulated recipients demonstrated focal chronic interstitial inflammatory infiltrates with tubular atrophy and relative sparing of the glomeruli. The development of immune responses to tissue-specific alloantigens may become of clinical significance as graft-survival times are increased.

The contributions of adrenal hormones, hemodynamic factors, and the endotoxin-related stress reaction to stable prostaglandin analog-induced peripheral lymphopenia and neutrophilia.

Stable prostaglandin analogs are known to induce lymphopenia and neutrophilia in a dose-dependent fashion after subcutaneous injection in rats. The purpose of the present investigation is to determine whether the prostaglandin-induced changes in circulating leukocytes might be secondary to hypotension with the ensuing release of adrenal hormones. The adrenal medullary catecholamine epinephrine was found to induce neutrophilia in both intact and adrenalectomized rats, and the glucocorticosteroid analog dexamethasone induced a profound lymphopenia in rats as reported by previous investigators. A stable analog of PGF2 alpha (15-S-15-methyl PGF2 alpha; M-PGF2 alpha) at the dose of 1 mg/kg induced marked systemic hypotension 1 h after injection, with lymphopenia and neutrophilia 6 h after injection. The non-prostanoid hypotensive agent captopril, at a dose of 63 mg/kg, induced a hypotension of similar magnitude and kinetics to that induced by prostaglandin. Captopril also induced lymphopenia and neutrophilia at 6 h, although the neutrophilia was of lesser magnitude than that induced by prostaglandins. The prostaglandin-induced lymphopenia was found to be mediated, at least in part, by the hypotension-induced release of adrenal hormones, as evidenced by the abrogation of lymphopenia in prostaglandin-treated adrenalectomized rats. Captopril-treated adrenalectomized rats, however, did develop a significant lymphopenia, suggesting that hypotension can result in lymphopenia even in adrenalectomized rats. The M-PGF2 alpha-induced neutrophilia in adrenalectomized rats, by comparison to captopril-induced neutrophilia in adrenalectomized rats, was greater than the neutrophilia expected as the result of hypotension alone. Indeed, the M-PGF2 alpha-induced neutrophilia in adrenalectomized rats was greater than the captopril-induced neutrophilia in sham-adrenalectomized rats. Thus, a portion of the neutrophilia induced by M-PGF2 alpha in intact rats may be mediated through adrenal-independent, hemodynamic-independent mechanisms. The possibility that M-PGF2 alpha might be inducing neutrophilia via an endotoxin-like stress reaction was investigated by examining changes in circulating white blood cells in intact and adrenalectomized C3H/HeN (endotoxin-sensitive) and C3H/HeJ (endotoxin-resistant) mice after prostaglandin administration. No quantitative differences in the prostaglandin-induced neutrophilia were noted in C3H/HeJ mice as compared to the C3H/HeN mice.(ABSTRACT TRUNCATED AT 400 WORDS)

Kinetics and mechanisms of recombinant human interleukin 1 and tumor necrosis factor-alpha-induced changes in circulating numbers of neutrophils and lymphocytes.

Human recombinant interleukins 1 alpha and 1 beta (rIL-1 alpha and -1 beta) both induced monophasic peripheral neutrophilia and lymphopenia in Lewis rats 1.5 hr after i.v. injection. The kinetics of rIL-1 alpha- and -1 beta-induced neutrophilia were similar to those induced by human monocyte-derived IL-1, IL-1 alpha, and IL-1 beta, and the peripheral neutrophilia was accompanied by a marked decrease in marrow neutrophils. Arachidonic acid metabolites are implicated as biochemical intermediates in the production of the neutrophilia but not lymphopenia, since indomethacin and dexamethasone both completely abrogated IL-1-induced neutrophilia but did not affect the IL-1-induced lymphopenia. Acetylsalicylic acid, a cyclooxygenase inhibitor, did not inhibit IL-1-induced neutrophilia, suggesting that products of the lipoxygenase rather than the cyclooxygenase pathway of arachidonate metabolism may contribute to the neutrophilia. Human recombinant tumor necrosis factor-alpha (rTNF) administered i.v. to Lewis rats induced peripheral neutropenia, two peaks of neutrophilia, and lymphopenia. A wide range of doses of rTNF resulted in an initial neutropenia at 0.5 hr after injection followed by a first peak of neutrophilia at 1.5 hr and a second peak of neutrophilia at 6 hr. The initial neutropenia and the first peak of neutrophilia were not inhibited by pretreatment of rats with dexamethasone, indomethacin, or aspirin. The second peak of neutrophilia was inhibited by both dexamethasone and indomethacin, but was not at all inhibited by aspirin, suggesting that the second peak of neutrophilia is mediated by the release of endogenous cytokines, especially by IL-1, since exogenous IL-1-induced neutrophilia is also completely inhibited by dexamethasone and indomethacin but not by aspirin. The TNF-induced peripheral neutrophilia is also accompanied by a significant depletion of bone marrow neutrophils, indicating that the source of increased circulating neutrophils is, at least in part, via recruitment of marrow neutrophils. Systemic blood pressure was not affected by IL-1 or rTNF at the dosages employed, showing that the changes in circulating leukocyte subsets were not attributable to hemodynamic changes nor to the hemodynamic change-related release of adrenal hormones. Adrenalectomy did not alter the IL-1- or rTNF-induced neutrophilia or lymphopenia, also demonstrating that neither monokine mediates its hematologic effects on peripheral blood leukocytes via the release of adrenal hormones.(ABSTRACT TRUNCATED AT 400 WORDS)

Stable analogs of prostaglandins E1 and F2 alpha ameliorate the proteinuria of aminonucleoside-of-puromycin nephrosis in Lewis rats.

Prostaglandins have been implicated by previous investigators in the pathogenesis of the nephrotic syndrome. A single subcutaneous injection of 1 mg/kg of stable analogs of prostaglandins E1 or F2 alpha (15[S]-15-methyl -PGE1 [M-PGE1] and -PGF2 alpha [M-PGF2 alpha]) was found in the present study to dramatically decrease proteinuria on Day 10 of puromycin aminonucleoside (PAN) nephrosis in Lewis rats. The decrease in proteinuria was mediated at least in part by a decrease in glomerular filtration rate (GFR), as quantitated by inulin clearances in nephrotic control and prostaglandin-treated rats. M-PGE1, moderately, and M-PGF2 alpha, to a lesser degree, also decreased the GFR in normal rats. Interestingly, the GFR was dramatically decreased in nephrotic as compared with nonnephrotic control rats, which suggests that PAN nephrosis may not be an ideal experimental model for human minimal change nephrosis in which the GFR is usually not severely compromised. The prostaglandin-induced decrease in GFR in both nephrotic and normal rats was coincident with a drop in systemic blood pressure. Nephrotic rats, however, had a slightly higher baseline blood pressure than normals, and the hypotensive effects of both prostaglandins were much less in nephrotic than in normal rats. The decrease in proteinuria was not related to a cytoprotective effect, as indicated by the failure of daily doses of 5 micrograms/kg M-PGE1 to reduce proteinuria 6, 8, or 10 days after injection of puromycin aminonucleoside. The similar antiproteinuric effects of prostaglandin synthesis inhibitors and of pharmacologic doses of prostaglandins are somewhat paradoxical but are reminiscent of the similarly paradoxical mutual antiinflammatory effects of these agents. The high doses of prostaglandins required to reduce proteinuria as well as their reduction of blood pressure and GFR will limit their clinical usefulness in the nephrotic syndrome.

The effects of a stable analogue of PGE1 on the IgG subclass response to particulate bovine tubular basement membrane in the brown-Norway rat.

The IgG subclass and the IgM isotype response to immunization with particulate bovine tubular basement membrane (TBM) and adjuvants was studied in Brown-Norway rats receiving daily injections of a stable analogue of PGE1 (M-PGE1). M-PGE1 slightly reduced the average quantity of circulating TBM antibody as well as the average quantity of eluted IgG per gram of renal tissue as compared to controls. However, M-PGE1 did not qualitatively affect the distribution of the IgG subclass or IgM isotype response to TBM. The IgG response, which occurred predominantly in the IgG1 and IgG2a subclasses, increased from Days 8 to 14 after immunization, while the IgM response decreased over the same time period. The percentage of TBM antibody in the IgG2b subclass was markedly decreased as compared to the percentage of IgG2b antibody in total IgG. A substantial heterogeneity in the IgG subclass response was noted among individual rats with IgG1 constituting from 46 to 82% of circulating TBM antibody. Although no correlation between the IgG subclass response and the severity of tubulointerstitial nephritis was noted, heterogeneity in the IgG subclass response to autoantigens may, nevertheless, theoretically play an important role in the pathogenesis of autoimmune inflammatory phenomena.

Inhibition of experimental autoimmune tubulointerstitial nephritis in Brown-Norway rats by (15S)-15-methyl prostaglandin E1. Analysis of the effect of prostaglandin E1 on the induction of the humoral immune response and the elicitation of humorally mediated inflammation.

Brown-Norway (BN) rats develop tubulointerstitial nephritis (TIN) after immunization with bovine tubular basement membrane (TBM) and adjuvants. Daily subcutaneous injections (either on Days 0-7 or Days 0-14) of (15S)-15-methyl prostaglandin E1 (M-PGE1) at a dose of 1 mg/kg/day markedly inhibited or completely abrogated the development of both the acute polymorphonuclear (Day 10) and the subsequent mononuclear (Day 14) inflammatory phases of BN rat TIN. Circulating anti-TBM antibody in Days 0-7 M-PGE1-treated rats was moderately diminished on Day 8 after immunization but not on Day 14. Circulating anti-TBM antibody in Days 0-14 M-PGE1-treated rats was only slightly diminished on Day 14. In experiments to test the effect of M-PGE1 on the elicitation phase of humorally mediated inflammation, M-PGE1 inhibited the acute inflammatory response observed 6 hours after intradermal injection of particulate TBM into TBM-sensitized BN rats. The inflammation in these skin tests was demonstrated by passive transfer experiments to be humorally mediated. The inhibition of acute humorally mediated intradermal inflammation was not attributable to neutropenia, because M-PGE1 caused a significant neutrophilia as demonstrated by peripheral blood smears. Although the inhibition of TIN in Days 0-14 M-PGE1-treated rats may have been due, in part, to dysfunction of the elicitation phase of humorally mediated inflammation, the inhibition of TIN in Days 0-7 M-PGE1-treated rats was more likely secondary to the diminished induction of either humoral or cellular immunity.

In vivo induction of neutrophilia, lymphopenia, and diminution of neutrophil adhesion by stable analogs of prostaglandins E1, E2, and F2 alpha.

Stable analogs of prostaglandins E1, E2, and F2 alpha (M-PGE1, DM-PGE2, and M-PGF2 alpha) were found to induce marked changes in circulating white blood cell subsets in Brown-Norway rats after subcutaneous injection. Dose-response studies demonstrated that 1000 micrograms/kg of each prostaglandin induced a maximum neutrophilia in the range of 40-70% of the total white blood cell count (normal, 5-20%) and that as little as 5 micrograms/kg of M-PGE1 induced a significant neutrophilia (P less than 0.05). Kinetic studies demonstrated that the maximum neutrophilia occurred 4-6 hours after injection of each prostaglandin and was not accompanied by the release of morphologically immature neutrophil forms from the bone marrow. Splenectomy slightly diminished the average neutrophilia at 2 hours but not at 4-6 hours after injection, which suggests that release of neutrophils from the spleen partially contributed to the early neutrophilia. Adherence experiments employing whole heparinized blood from rats given prostaglandins 6 hours prior to sacrifice demonstrated that neutrophils exposed to prostaglandins in vivo have diminished adherence to nylon wool columns, which suggests that diminished adherence of the marginated neutrophil pool may contribute to the neutrophilia. The prostaglandin-induced neutrophilia was accompanied not by a significant change in total numbers of circulating white blood cells, but, rather, by a significant decrease in circulating mononuclear white blood cells, including T-helper, T-suppressor, and B cells. The combination of neutrophilia with lymphopenia has classically been attributed to the release of adrenal hormones and suggests 1) that prostaglandins may directly or indirectly cause the release of adrenal hormones, or 2) that adrenal hormones may mediate their effects on circulating white blood cell subsets via prostaglandins, or 3) that prostaglandins activate intracellular messenger systems that are also activated by adrenal hormones.

(15S)-15-methyl prostaglandin E1-induced neutrophilia in Brown-Norway rats.

A stable analogue of prostaglandin E1, (15S)-15-methyl prostaglandin E1 (M-PGE1), induces a marked relative and absolute neutrophilia after subcutaneous injection at a pharmacologic dose of 1 mg/kg in Brown-Norway rats. The neutrophils reached a peak of 6 hours after injection at which time the absolute neutrophil count was 13,457 +/- 6,038/mm3 versus 2,451 +/- 1,298/mm3 before injection (p less than 0.001). The absolute white blood cell count/mm3 did not change significantly at 6 hours after injection, but a significant eosinopenia was noted, as has been described by previous investigators, after the administration of prostaglandins. A possible physiologic in vivo role for prostaglandin in the causation of neutrophilia remains to be elucidated.