Alterations of Circadian Rhythms in Mice Induced by Anti-Cancer Drugs

Carboplatinum was injected into four groups of mice for 5 successive days at one out of four daily equidistant hours. Upon the cessation of these injections, granulocyte colony stimulating factor was injected into half of these mice for 2 days at the same times. The stimulating factor was also injected into groups of untreated mice for 2 days at the same times. In each experiment the rhythms of four variables were monitored after the cessation of all injections: peripheral WBC count, bone marrow and sperm stem cells DNA synthesis, and sperm ribosomal RNA content. The results indicated that in the course of repeated drug administrations, variables' rhythm parameters (phases and periods) were altered. These changes have to be considered in chronotherapeutic schedules when variables which serve for toxicity diagnosis or as drug target are rhythmic in nature.     

Immediate and Prolonged Effects of Drugs on Rhythm's Characteristics: Relevance to Chronochemotherapy

Four groups of mice were injected with vincristine, each at a different time, for ten successive days. Mortality and daily pattern of peripheral white blood cells (WBC) count were monitored immediately and at various times after the last injection. The results demonstrated that (1) drug administration time dependency was observed in rate of death, recorded for 80 days following the injections; (2) the time of drug administration affected the parameters of WBC count rhythm, and (3) there were differences between immediate effects upon the rhythm parameters (monitored one day after the last injection) to those measured at succeeding times (on days 8 and 15 after injections cessation). The results emphasize the need to consider continuous post administration rhythm changes, especially when scheduling repeated chronotherapeutics, where variables which serve for toxicity-diagnosis are rhythmic in nature.     

Immediate and Prolonged Effects of Drugs on Rhythm's Characteristics: Relevance to Chronochemotherapy

Four groups of mice were injected with vincristine, each at a different time, for ten successive days. Mortality and daily pattern of peripheral white blood cells (WBC) count were monitored immediately and at various times after the last injection. The results demonstrated that (1) drug administration time dependency was observed in rate of death, recorded for 80 days following the injections; (2) the time of drug administration affected the parameters of WBC count rhythm, and (3) there were differences between immediate effects upon the rhythm parameters (monitored one day after the last injection) to those measured at succeeding times (on days 8 and 15 after injections cessation). The results emphasize the need to consider continuous post administration rhythm changes, especially when scheduling repeated chronotherapeutics, where variables which serve for toxicity-diagnosis are rhythmic in nature.     

High incidence of scrapie induced by repeated injections of subinfectious prion doses

To clarify the mechanisms leading to the development of Creutzfeldt-Jakob disease in some recipients of pituitary-derived human growth hormone (hGH), we investigated the effects of repeated injections of low prion doses in mice. The injections were performed, as in hGH-treated children, by a peripheral route at short intervals and for an extended period. Twelve groups of 24 mice were intraperitoneally inoculated one, two, or five times per week for 200 days with 2 x 10(-5) to 2 x 10(-8) dilutions of brain homogenate containing the mouse-adapted C506M3 scrapie strain. Sixteen control mice were injected once a week for 200 days with a 2 x 10(-4) dilution of normal brain homogenate. Of mice injected in a single challenge with a scrapie inoculum of a 2 x 10(-4), 2 x 10(-5), or 2 x 10(-6) dilution, 2/10, 1/10, and 0/10 animals developed scrapie, respectively. Control mice remained healthy. One hundred thirty-five of 135 mice injected with repeated prion doses of a 2 x 10(-5) or 2 x 10(-6) dilution succumbed to scrapie. Of mice injected with repeated scrapie doses of a 2 x 10(-7) or 2 x 10(-8) dilution, 52/59 and 38/67 animals died of scrapie, respectively. A high incidence of scrapie was observed in mice receiving repeated doses at low infectivity, whereas there was no disease in mice that were injected once with the same doses. Repeated injections of low prion doses thus constitute a risk for development of prion disease even if the same total dose inoculated in a single challenge does not induce the disease.     

Influence of Onabotulinumtoxin A on testes of the growing rat

Onabotulinumtoxin A (onabotA) is gaining wide medical use in children. The present study was planned to investigate the influence of its injection on the maturing testicular structures in rats. Immature rats were injected in the bilateral cremaster muscles by onabotA with three doses of (10, 20, and 40 U/kg) three times in a 2‐week interval. The effect of these injections on fertility indices was examined. Levels of antisperm antibodies and several apoptosis parameters were also investigated. DNA content in form of ploidy and histopathological alterations were assessed. OnabotA‐injected groups showed decreased sperm count and semen quality, while sperm vitality, morphology, and testosterone levels were not significantly affected. Furthermore, DNA flow cytometric analysis confirmed delayed sperm maturation. Apoptosis markers were significantly increased by the injections. In conclusion, onabotA injection in growing rats adversely affected sperm count and maturation. OnabotA testicular effects are mediated, at least partly, by apoptosis.     

Increased sperm output of rabbits and bulls treated with prostaglandin F2α

Seven rabbits were ejaculated four times once weekly, and saline or 2.5 mg PGF_2α tromethamine salt was injected sc at 4 and 2 hours or at 8 and 4 hours before ejaculation. First ejacula taken at 2 hours after the second injection of PGF_2α contained 150% more (P.07) sperm than those after injections of saline. The comparable difference (60%) at 4 hours after PGF_2α was not significant. PGF_2α did not influence sperm output in second, third or fourth ejacula. After 28 daily sc injections of 5 mg PGF_2α in another experiment, the fertility of four treated rabbits was as high as that for four controls. Without sexual preparation in seven bulls, im injections of 40 or 80 mg PGF_2α 30 minutes before ejaculation resulted in 33% greater (P<.05) sperm output than that after injection of 0, 7 or 20 mg PGF_2α, but the highest sperm output after PGF_2α was 30% less (P<.05) than that after sexual preparation in the same bulls. We conclude that injections of PGF_2α result in increased sperm output in ejacula taken without sexual preparation within 2 hours in rabbits and in bulls.     

Studies on lidocaine-induced kindling.

Lidocaine HCl, injected 5 times weekly, produces pharmacological kindling in rats. The aims of the present study were to: 1) approximate the threshold dose for the effect in mice and 2) determine if injections given less frequently than 5 times weekly produces kindling. Mice were injected (IP) either 5 times weekly for 4 weeks or 2 times weekly for 10 weeks, with doses ranging from 30 to 50 mg/kg. Kindling was defined as the appearance of convulsions on each of 5 consecutive injections. The estimated threshold dose for kindling was approximately 40 mg/kg, as suggested by the observation that 2 of 8 and 8 of 8 mice were kindled at 40 and 50 mg/kg respectively when injected 5 times each week. Whether mice were injected (50 mg/kg) 5 times weekly, or, only twice weekly, 80% of them were kindled by the fifteenth injection. Thus, it would appear that pharmacological kindling might be as much a function of number of injections as it is of frequency of injections.     

Microbial adjuvant and autoimmunity. II. Production of lesions in mice immunized with syngeneic tissue extracts together with the capsular polysaccharide of Klebsiella pneumoniae.

The target organs of mice immunized with the respective syngeneic tissue extracts together with the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) as a powerful adjuvant were examined for production of lesions. In 15 out of 24 mice injected three times or more with syngeneic eyeball extracts and CPS-K adjuvant at intervals approximately 30 days, severe eyeball lesions developed in which the normal structure was almost completely lost. A large part of the eyeball tissue of these mice was replaced by infiltration with cells such as lymphocytes, plasma cells and other mononuclear cells and by connective tissue. No definite eye lesions developed in mice injected with CPS-K alone, eyeball extracts alone or eyeball extracts emulsified in complete Freund's adjuvant (CFA). In all of mice injected four times with thyroid gland extracts and CPS-K at intervals of approximately 30 days, definite thyroid gland lesions were produced. In three out of five mice of this group, the thyroid lesions were so severe that the normal thyroid follicular structure was almost completely lost, and a large part of the thyroid gland was replaced by infiltration with lymphocytes, plasma cells and other mononuclear cells and in part by connective tissue. In only one out of five mice injected with thyroid gland extracts emulsified in CFA, definite but milder thyroid gland lesions developed. No definite thyroid lesions developed in the remaining four mice of this group and also in any of the mice injected with thyroid gland extracts alone or CPS-K alone. Repeated injections of lymphoid tissue extracts and CPS-K also induced pathological changes in the spleen and lymph nodes, although less marked than those in the cases of the eyes and thyroid gland. The most remarkable change was a decrease in numbers of small lymphocytes at the areas surrounding the central arterioles in the white pulp of the spleen and the post-capillary venules in the cortex of the lymph nodes. From these results it has been concluded that our system can provide new and useful models for autoimmune diseases in man.     

Reproductive toxicity in male mice caused by organic extracts in tap water from the Jialing River in Chongqing, China

BACKGROUND : Recently, male reproductive disturbances caused by organic pollutants have aroused particular public concern about the safety of drinking water. The aim of this study was to investigate the toxicity of organic extracts (OE) in tap water from the source of the Jialing River in China on the reproductive system of male mice. METHODS : Kunming male mice were randomly divided into four groups, which included a solvent control (dimethylsulfoxide), a low‐, mid‐, and high‐dose of OE (12.5, 25, and 50 l/kg bw/day, respectively) treated groups. Mice were administered intraperitoneal injections of OE at different doses for five consecutive days. On the 15th day, after treatments, the mice were sacrificed. RESULTS : The results showed that the number of epididymal sperm in the high OE group was decreased significantly (p<0.05); however, the frequency of sperm abnormalities in all treated groups were increased significantly (p<0.05). In addition, serum testosterone and follicle‐stimulating hormone levels in the treated groups were also decreased significantly (p<0.05), and mid‐ and high‐doses of OE resulted in a significant decrease in the activity of acid phosphatase and increased activity of γ‐glutamyl transpeptidase (p<0.05). Histological changes were observed in the mid‐ and high‐dose OE‐treated groups. CONCLUSIONS : The findings of this study suggest that mid and high doses of OE could disturb the male reproductive system in mice. The potential adverse effects of these compounds on the male reproductive system are worthy of further study. Birth Defects Res (Part B) 92:1–9, 2010. © 2011 Wiley‐Liss, Inc.     

Sex control by Zfy siRNA in the mouse

The objective of this work was to detect the influence of Y sperm forming of Mus musculus by silencing the Zfy gene during spermatogenesis. The recombination expression vectors pSilencer5.1/Zfy215 and pSilencer5.1/Zfy2102 were constructed. 64 male KunMing Mus were divided into four groups randomly and averagely. The two recombination expression vectors were injected into two groups, respectively, through testis. The other two groups were injected with the same volume of physiological saline and empty vector pSilencer5.1-H1 Retro, respectively. They were injected every ten days for a total of four injections. Seventeen days after the fourth injection, 8 male Mus of each group mated with 8 female Mus. The testis tissue of the other 8 male Mus of each group was collected, and the expression level of Zfy mRNA was determined by fluorescence quantitation real time PCR (qRT-PCR). The result showed that the expression of Zfy mRNA decreased significantly after injection of pSilencer5.1/Zfy2102 (P < 0.01), and that 72.3% of the offspring were female, a number significantly higher than in the control group (P < 0.01). In the pSilencer5.1/Zfy215 group, the expression of Zfy mRNA was significantly lower than in the control group (P < 0.05), but the female rate of offspring was not. It was concluded that the Zfy gene could play a role in the process of Y sperm formation.     

Sustained cell proliferation in denervated skeletal muscle of mice

Summary Cellular proliferation in skeletal muscle was measured throughout the first 4 weeks after denervation. Twenty four mice had one leg denervated, and 4 groups of 6 of these mice were injected with tritiated thymidine once daily for 7 days, either during the first, second, third or fourth week after denervation. Autoradiographic labelling of muscle and connective tissue nuclei in denervated muscles was compared with innervated muscles from the opposite innervated legs of the same mice. Labelling of connective tissue and muscle (myonuclear and satellite cell) nuclei was significantly higher in denervated muscles, compared with innervated muscles on the unoperated side. There were no significant differences among labelling of nuclei in muscles denervated for 1, 2, 3 or 4 weeks. However, connective tissue labelling after 1 week of denervation was significantly higher than at later times. This study shows that nuclei of muscle and connective tissue cells proliferate and turnover at high levels for at least one month after denervation.     

Studies on DNA repair in early spermatid stages of male mice after in vivo treatment with methyl-, ethyl-, propyl-, and isopropyl methanesulfonate.

In vivo DNA repair occurring in early spermatid stages of the mouse has been studied with four mutagens that are chemical homologs: MMS, EMS, PMS and IMS. Using the well-studied sequence of events that occurs during spermatogenesis and spermiogenesis in the mouse, aatids was measured by the unscheduled incorporation of [3H]dT into these germ cells which were recovered from the caudal epididymides 16 days after chemical treatment. Purification of the caudal sperm DNA at this time verified that the [3H]dT was incorporated into the DNA. For each chemical mutagen a study was made on the level of DNA repair occurring in early spermatids as a function of the administered, in vivo dose. Within experimental errors, all four chemicals produced a linear increase in DNA repair in early spermatids with increasing dose. Only the highest dose of MMS (100 mg/kg) produced a greater repair response than expected for a linear curve. At equimolar doses the most effective chemical in inducing DNA repair was MMS, followed by EMS, IMS and PMS. When testicular injections of [3H]dT were given at the same time as the intraperitoneal injections of the mutagens, the amount of unscheduled incorporation of [3H]dT into the DNA of early spermatids was maximized. Since [3H]dT has been shown to be available for incorporation into germ-cell DNA for only approximately 1 h after injection, all four mutagens must reach the DNA of early spermatids and begin producing "repairable" lesions within 1 h after treatment. The amount of DNA repair occurring at later times after chemical treatment of early spermatids was studied by testicular injections of [3H]dT 1/2, 1, 2 and 3 days after chemical treatment. Repair was still occurring in the early spermatids at 3 days post-treatment; this repair is most likely a manifestation of the finite rate of the repair process rather than resulting from newly alkylated DNA. For MMS and EMS there was a rapid decrease in the level of DNA repair in the first 1/2 day following treatment. This was followed by a much slower, exponential decrease in the level of repair out to 3 days post-treatment. The curves suggest that the amount of repair is proportional to the number of repairable lesions still present in the DNA. For PMS and IMS the level of repair decreases rapidly in the first 1/2 day after treatment and thereafter remains relatively constant through 3 days post-treatment. With all four mutagens, DNA repair in early spermatids was detectable at doses 5 to 10 times lower than those required to observe other genetic end points such as dominant lethals, translocations and specific-locus mutations in any germ-cell stage. The sensitivity of detection of in vivo DNA repair in the germ cells of male mice makes such a system a useful adjunct to other genetic tests for studying chemical mutagenesis in mammals.     

Influence of purified recombinant human macrophage colony stimulating factor in mice

The endotoxin-resistant strain of mouse, C3H/Hej, was assessed for hematological responsiveness to multiple injections of high dosages of purified recombinant human macrophage colony stimulating factor (rhu-M-CSF). Mice were administered the rhu M-CSF i.p. at dosages of 40 micrograms per injection, 2 or 3 times per day for 4 days. This resulted in significant increases in circulating leukocytes compared to control mice given sterile pyrogen-free saline. Assessment of the marrow and spleen of these mice on the 5th day noted a significant reduction in the numbers of marrow hematopoietic progenitor cells, with no change in their cycling rates. In contrast, splenic granulocyte-macrophage and erythroid progenitor cell numbers were markedly increased and the cycling rates of these progenitors plus those of multipotential progenitors were significantly enhanced. Marrow and splenic early myeloid cells (blasts, promyelocytes, and myelocytes) and macrophages were increased, while marrow and splenic PMN were decreased. The results suggest that multiple injections of high dosages of rhu-M-CSF to previously untreated mice for a short period of time has a modest enhancing effect on blood leukocyte levels. This is associated with a shift of hematopoietic cell activity from the marrow to the spleen.     

Validation of a heterologous fertilization assay and comparison of fertilization rates of equine oocytes using in vitro fertilization,perivitelline, and intracytoplasmic sperm injections

IVF in horses is rarely successful. One reason for this could be the failure of sperm to fully capacitate or exhibit hyperactive motility. We hypothesized that the zona pellucida (ZP) of equine oocytes prevents fertilization in vitro, and bypassing the ZP would increase fertilization rates. Limited availability of equine oocytes for research has necessitated the use of heterologous oocyte binding assays using bovine oocytes. We sought to validate an assay using bovine oocytes and equine sperm and then to demonstrate that bypassing the ZP using perivitelline sperm injections (PVIs) with equine sperm capacitated with dilauroyl phosphatidylcholine would result in higher fertilization rates than standard IVF in bovine and equine oocytes. In experiment 1, bovine oocytes were used for (1) IVF with bovine sperm, (2) IVF with equine sperm, and (3) intracytoplasmic sperm injections (ICSIs) with equine sperm. Presumptive zygotes were either stained with 4′,6-diamidino-2-phenylindole from 18 to 26 hours at 2-hour intervals or evaluated for cleavage at 56 hours after addition of sperm. Equine sperm fertilized bovine oocytes; however, pronuclei formation was delayed compared with bovine sperm after IVF. The delayed pronuclear formation was not seen after ICSI. In experiment 2, bovine oocytes were assigned to the following five groups: (1) cumulus oocyte complexes (COCs) coincubated with bovine sperm; (2) COC exposed to sucrose then coincubated with bovine sperm; (3) COC coincubated with equine sperm; (4) COC exposed to sucrose, and coincubated with equine sperm; and (5) oocytes exposed to sucrose, and 10 to 15 equine sperm injected into the perivitelline (PV) space. Equine sperm tended (P = 0.08) to fertilize more bovine oocytes when injected into the PV space than after IVF. In experiment 3, oocytes were assigned to the following four groups: (1) IVF, equine, and bovine COC coincubated with equine sperm; (2) PVI of equine and bovine oocytes; (3) PVI with equine oocytes pretreated with sucrose; and (4) ICSI of equine oocytes. Oocytes were examined at 24 hours for cleavage. No equine oocytes cleaved after IVF or PVI. However, ICSI conducted with equine sperm treated with dilauroyl phosphatidylcholine resulted in 85% of the oocytes cleaving. Sperm injected into the PV space of equine oocytes did not appear to enter the ooplasm. This study validated the use of bovine oocytes for equine sperm studies and indicates that failure of equine IVF is more than an inability of equine sperm to penetrate the ZP.     

Leishmania tropica: protective response in C3H mice vaccinated with excreted factor crosslinked with the synthetic adjuvant, muramyl dipeptide

Excreted factor, an immunosuppressive, acidic polysaccharide released by promastigotes of Leishmania tropica major in culture, was chemically crosslinked to the synthetic adjuvant muramyl dipeptide via the bifunctional imidoester dimethyladipimidate and poly-L-lysine. This conjugate, an uncrosslinked mixture of the components, or each of the components alone were injected one to three times into different groups of 8- to 12-week-old C3H mice. The mice were challenged 2 weeks after the last injection with 2 X 10(6) promastigotes of L. t. major in the base of the tail. For the next 5 weeks, the animals were monitored for number of parasites and size of the lesion which developed at the site of the challenge. Mice receiving one intraperitoneal injection of the conjugate were partially protected against challenge. Treated animals had higher initial parasite numbers but showed a more rapid clearing of the parasites. Furthermore, the treated animals developed smaller lesions that healed quicker than did those of the control groups. Multiple injections, or injection into a footpad, rather than intraperitoneally, reduced the ability to elicit a protective response. On the other hand, muramyl dipeptide injected into a footpad was partially protective. Antibody production to excreted factor, which was measured by indirect hemagglutination of sensitized erythrocytes, was detected after challenge in mice which had received conjugate or conjugate components. A delayed hypersensitivity reaction (measured by skin testing) was not detected in any of the groups prior to challenge.     

Mouse sperm antigens that participate in fertilization. III. Passive immunization with a single monoclonal antisperm antibody inhibits pregnancy and fertilization in vivo

Passive immunization was used to study the effect of antimouse sperm monoclonal antibodies on fertilization in vivo. The effects of two antibodies were compared in this investigation. One of them, M29, has been shown previously to localize to the equatorial segment of the sperm head and to inhibit mouse fertilization in vitro in a concentration-dependent manner. The second antibody, M2, binds to the same area of the sperm head, and also belongs to the M immunoglobulin class (IgM), but does not affect fertilization in vitro. Superovulated female mice received two antibody injections intraperitoneally (at the times of the pregnant mare's serum gonadotropin and human chorionic gonadotropin injections) at concentrations of 0.5-4.0 mg of IgM or control IgG; animals were mated within 6-12 h of the hCG injection. Fertilization and concomitant establishment of pregnancy were reduced significantly, in a dose-dependent manner, only in those animals immunized with M29 IgM (e.g., 4 mg M29 IgM: 12.6% of 304 eggs fertilized; 4 mg M2 IgM: 96% of 192 eggs fertilized). Intraperitoneal administration of the antibodies did not depress superovulation levels nor oocyte viability. 125I-labeled M29 IgM was used to determine the amount of antibody present in the oviductal ampulla at the time of fertilization in passively immunized mice. Luminal M29 IgM was found to be a linear function of the intraperitoneal dose: 0.002-0.003% of the injected dose was present in the oviductal lumen 14-16 h post-hCG.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of long-term administration of either a crude inhibin preparation or an antiserum to FSH on serum hormone levels, testicular function and fertility of adult male rats.

Adult male rats were given either daily injections of ram rete testis fluid for periods of up to 70 days or injections of an antiserum against FSH every 3 days for 90 days. Compared with the control groups, the rats injected with ram rete testis fluid had lowered serum FSH levels, but only at treatment periods of 30 days and less. The levels of LH and testosterone in serum, testicular fluid secretion, sperm counts, testis weights and fertility were not affected by rete testis fluid treatment. The rats injected with anti-FSH serum exhibited an impairment of fertility which was never complete and evident only after 49 days of treatment. After 90 days of anti-FSH treatment, testis weight and free serum FSH were reduced, but sperm counts, testicular fluid secretion and serum levels of LH and testosterone were not affected.     

Long-term comparative effect of cholecystokinin and gastrin on mouse stomach, antrum, intestine, and exocrine pancreas

Mice were injected three times a day for 12 days with 300 micrograms/kg body weight of gastrin G17 or 37.5 Ivy dog U/kg body weight of CCK or saline. Other mice were also injected four times an hr for 1 hr with 7.5 micrograms/kg of gastrin, nine Ivy dog U/kg of CCK or saline; 1 hr before killing, they were injected with tritiated thymidine to evaluate the labelling indices in peptic, antral, duodenal, jejunal, and ileal mucosae. Four hours after the first injection of the two peptides, the peptic labelling indices increased while those of intestinal mucosa increased 8 hr after these injections. Long-term injections of CCK had a trophic effect on secretory cells of the digestive tract: the number of gastric zymogenic cells, Paneth cells, and the mucous cells of Brünner glands were hypertrophied. The pepsin, amylase, chymotrypsin, and lysozyme activities increased in stomach, exocrine pancreas, and intestine, respectively. Neither parietal cells nor intestinal enterocytes and hydrolase activities were affected. The trophic effect of long-term injections of gastrin is confirmed on parietal cells and exocrine pancreatic parenchyma and is demonstrated in Paneth cells. Confirming cytological results, pancreatic lipase and amylase activities and intestinal lysozyme activity were increased after gastrin. Although CCK and gastrin have a structural analogy, these two peptides did not affect the same cellular types. A specific action of CCK on the main secretory cells of the digestive mucosa is demonstrated.     

Behavioral dependence on phencyclidine in rats

The abuse of PCP continues to be an important medical problem in many urban areas. The probability that dependence on PCP may contribute to its compulsive use and relapse is supported by animal studies demonstrating its dependence liability. In the present study, five rats were housed in operant chambers and trained to respond on a lever under a fixed-ratio 30 schedule of food presentation. They obtained all their daily food during four 30-min response periods occurring every 6 hr. After stable baselines of behavior were established the rats were injected with PCP (3.0-7.5 mg/kg/injection), i.p., 1 hr before each response session for 7-10 days. Following chronic dosing, the drug injections were replaced with saline injections for 10 days. Disruptions in behavior were observed upon cessation of relatively brief chronic exposure to PCP (as little as 7 days) and at relatively low doses (5.6 mg/kg/6 hr = 22.4 mg/kg/day). The behavioral disruption was not accompanied by overt signs of abstinence and persisted for up to 48 hr.     

Neonatal Semax and saline injections induce open-field behavior changes in mice of different genotypes

DBA/2, CBA mice, and their F1 hybrids (first series) and 101/HY and C3H mice (second series) were injected as neonates (2-7 days of life) with Semax (sc., 7 microg per animal). Semax is a peptide analogue of ACHT4-10 fragment which is resistant to degradation. The common feature of remote effects of both Semax and saline injections was the set of changes in the open-field behavior in adult (2.5- to 3-month-old) animals as compared to intact mice. Unexpectedly, the neonatal saline injections induced many changes in adult behavior, part of these effects being genotype-dependent. The most conspicuous shifts (genotype-dependent increase or decline) in freezing, grooming and rearing scores were displayed by DBA/2 and C3H mice, whereas the hole-poke frequencies were significantly changed in CBA and C3H mice. Squares crossed in the center of arena and rearing number were significantly increased in saline group of DBA/2 mice, whereas in Semax-injected DBA/2 group they were approximately equal to the level of intact mice. This means that the remote effects of noxious stimulation (injections of saline) were in some ways "compensated" as the result of concomitant peptide effect. At the same time, the numbers of freezing and grooming episodes were also increased in these groups. Because exploratory behavior and manifestations of anxiety increased or decreased simultaneously, it proves to be difficult to ascribe these changes to behavioral modulation along the "novelty seeking--anxiety" axis. In mice of other genotypes, changes in the same indices of the open-field behavior were revealed, but these changes were different in their direction. It was suggested that the complex patterns of postnatal behavior was the result of neonatal injections modulating subsequent brain development.