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L Uphouse

Publications and source records attributed to L Uphouse.

62 records · Page 4Linked to original sources

Effects of a novel experience on rat brain chromatin.

In this study adult Fischer, inbred rats experienced (1) training to avoid footshock (2) unavoidable footshock or (3) no training or footshock. Each animal was sacrificed at one of several time points (1-60 hours) following experience. Brain chromatin was extracted and used as template for RNA synthesis in vitro. Both groups which received the novel experience demonstrated greater template activity than the unshocked, untrained groups. This effect was brief. The two groups which received the experience did not differ from each other. These results suggest that a brief, novel experience can temporarily alter the transcriptional activity of brain chromatin.

Animals↗

Postovulatory reduction of fertility in chlordecone treated female rats.

The chlorinated pesticide, chlordecone, is widely recognized for its production of reproductive deficits. This reproductive sterility has been attributed to chlordecone's apparent "estrogenicity" and its ability to inhibit the release of luteinizing hormone (LH) from the anterior pituitary. However, it was recently noted that the pesticide could also reduce fertility when exposure was delayed until the day following ovulation. This led to the suggestion that chlordecone's actions on reproductive function continued into the postovulatory period. Results of the following studies substantiate this suggestion. Follicular development and ovulation were induced in immature female rats with a combined treatment of pregnant mare serum (PMS) and human chorionic gonadotropin (HCG). Chlordecone (25-75 mg/kg) administration at the time of PMS exposure did not inhibit the ovulatory response to HCG. Furthermore, when adult proestrous female rats were treated with chlordecone, normal numbers of ova were observed the following day. However, implantation sites were never observed in females that had been exposed to chlordecone. Moreover, offspring production was eliminated when mated females were exposed to doses of 50 or 75 mg/kg chlordecone on days 1, 2, or 3 following mating. In contrast, offspring production was normal when the exposure was delayed until the fourth day after mating. Since the vulnerable gestational period overlaps or precedes the time of implantation, these results suggest that ova viability and/or implantation is reduced by the chlordecone exposure.

Analysis of Variance↗

A single pretreatment with 8-OH-DPAT reduces behavioral indices of serotonin 1A receptor activation in ovariectomized rats.

The effects of prior treatment with 8-OH-DPAT on 8-OH-DPAT-induced eating behavior, hypothermia, flat body posture and forepaw treading were examined in ovariectomized rats. Twenty-four hours after a single pretreatment with 0.25 mg/kg of the drug, the eating behavior and flat body posture induced by 8-OH-DPAT were reduced relative to that seen following the first treatment with the drug. In contrast, within 24 hr of the prior drug treatment, the drug's effects on forepaw treading and rectal temperature were unchanged. However, 7 days after prior treatment with 8-OH-DPAT, eating behavior, flat body posture and hypothermia induced by the drug were suppressed. Only forepaw treading remained unchanged. These findings are discussed in reference to similar studies of 5-HT1A receptor agonist-induced modulation of behaviors in male rats.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Single injection with chlordecone reduces behavioral receptivity and fertility of adult rats.

The effects of chlordecone on fertility were examined in adult, intact female rats. Rats were treated with 25, 50 or 75 mg/kg chlordecone and initial exposure occurred either on the morning before mating or on the morning after mating. When exposure occurred on the morning of proestrus, mating behavior 8 to 9 hours was significantly reduced by 50 or 75 mg/kg chlordecone. Yet, when housed overnight with sexually experienced males, most females showed sperm in the vaginal smear. However, only 23% of the 50 mg/kg group and none of the 75 mg/kg group delivered offspring. Females given 25 mg/kg chlordecone showed behavior and fertility identical to oil injected controls. When females were treated with chlordecone after mating, 41% of the females given 50 mg/kg chlordecone produced litters while 33% of the 75 mg/kg females delivered offspring. Under both conditions, fertility was substantially reduced. In previous studies, chlordecone's reduction of the preovulatory luteinizing hormone (LH) surge has been offered as an explanation for the pesticide's reproductive deficits. The present studies indicate that the failure of chlordecone-treated females to ovulate cannot totally account for the decreased fertility.

Animals↗