Plasma progesterone levels and cocaine-seeking in freely cycling female rats across the estrous cycle

Feltenstein, Matthew W.; See, Ronald E.

doi:10.1016/j.drugalcdep.2006.12.017

Cited by 128 publications

(161 citation statements)

References 56 publications

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“…Previous studies report that hormonal fluctuations due to the estrous cycle can influence day-to-day variability in both running wheel activity (Steiner et al, 1982;Kent et al, 1991) and cocaine self-administration (Roberts et al, 1989;Feltenstein and See, 2007); however, it is unlikely that such day-to-day fluctuations could have accounted for the present results. For instance, on the PR schedule, all rats remained at a given dose until a stable breakpoint was reached.…”

Section: Discussioncontrasting

confidence: 57%

Aerobic exercise decreases the positive-reinforcing effects of cocaine

Smith

Schmidt

Iordanou

et al. 2008

Drug and Alcohol Dependence

136

146

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Aerobic exercise can serve as an alternative, non-drug reinforcer in laboratory animals and has been recommended as a potential intervention for substance abusing populations. Unfortunately, relatively little empirical data have been collected that specifically address the possible protective effects of voluntary, long-term exercise on measures of drug self-administration. The purpose of the present study was to examine the effects of chronic exercise on sensitivity to the positive-reinforcing effects of cocaine in the drug self-administration procedure. Female rats were obtained at weaning and immediately divided into two groups. Sedentary rats were housed individually in standard laboratory cages that permitted no exercise beyond normal cage ambulation; exercising rats were housed individually in modified cages equipped with a running wheel. After 6 weeks under these conditions, rats were surgically implanted with venous catheters and trained to self-administer cocaine on a fixedratio schedule of reinforcement. Once self-administration was acquired, cocaine was made available on a progressive ratio schedule and breakpoints were obtained for various doses of cocaine. Sedentary and exercising rats did not differ in the time to acquire cocaine self-administration or responding on the fixed-ratio schedule of reinforcement. However, on the progressive ratio schedule, breakpoints were significantly lower in exercising rats than sedentary rats when responding was maintained by both low (0.3 mg/kg/infusion) and high (1.0 mg/kg/infusion) doses of cocaine. In exercising rats, greater exercise output prior to catheter implantation was associated with lower breakpoints at the high dose of cocaine. These data indicate that chronic exercise decreases the positive-reinforcing effects of cocaine and support the possibility that exercise may be an effective intervention in drug abuse prevention and treatment programs.

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Section: Discussioncontrasting

confidence: 57%

Aerobic exercise decreases the positive-reinforcing effects of cocaine

Smith

Schmidt

Iordanou

et al. 2008

Drug and Alcohol Dependence

136

146

View full text Add to dashboard Cite

show abstract

“…Administering stimulants to female rats during estrus also induces increased behavioral activity (Sell et al 2002), self-administration of higher cocaine doses (Lynch et al 2000), and potentiation of drug reinstatement (Kippin et al 2005). Conversely, in proestrus rats, high levels of progesterone have been associated with significantly less cocaine seeking (Feltenstein and See 2007).…”

Section: Introductionmentioning

confidence: 99%

Altered levels of sex and stress steroid hormones assessed daily over a 28-day cycle in early abstinent cocaine-dependent females

et al. 2007

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Rationale-There is growing evidence of alterations in brain stress and reward circuits associated with cocaine dependence. Sex differences are also documented and sex steroid hormones have been linked to cocaine reinforcement.Objectives-The current study therefore assessed daily fluctuations in stress and sex hormones in cocaine-dependent females compared with healthy females.Method-Daily salivary samples of cortisol, progesterone, and estradiol were collected at waking across 28 days from 12 cocaine-dependent females receiving inpatient treatment and 10 healthy females. Participants also completed mood-rating scales each week corresponding to four phases of the menstrual cycle and cocaine craving was monitored in cocaine patients at each phase.Results-Cocaine-dependent females in their first month of abstinence demonstrated significantly higher levels of both cortisol and progesterone across the menstrual cycle and significantly lower estradiol/progesterone (E2/P) ratios compared to healthy controls. They also showed significantly increased negative mood compared with controls, but no variation in cocaine craving across the menstrual cycle.Conclusions-Findings indicate altered stress and sex hormones suggestive of an overactive stress system during the first month of cocaine abstinence after chronic cocaine abuse. These increased levels of cortisol and progesterone could impact both abstinence-related symptoms such as negative mood and susceptibility to drug-seeking behavior in cocaine-dependent females.

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“…However, a higher concentration of PNS may be needed to provide a higher input of progesterone in plasma. 45 …”

mentioning

confidence: 99%

Sustained-release progesterone nanosuspension following intramuscular injection in ovariectomized rats

Salem¹

2010

IJN

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Abstract:The production of an intramuscular (IM) injection of natural progesterone would provide a safer solution than using semi synthetic progesterone. However, disadvantages such as low solubility and a short half life prevent the use of natural progesterone. In this study, we formulated a sustained release form of natural progesterone to be given as IM injection. A progesterone nanosuspension (PNS) was first developed and then dispersed in a thermosensitive gel matrix. The selected nanoparticles showed an average particle size of 267 nm and a zeta potential approaching-41 mV. The in vitro release profile of PNS from the F127 plus methyl cellulose gel followed zero order kinetics and correlated linearly with the weight percentage of gel dissolved, demonstrating that the overall rate of release of PNS is controlled by dissolution of the pluronic F127/methyl cellulose (MC) gel (r 2 . 0.99). The pharmacokinetic parameters of the PNS (6 mg/mL) in pluronic F127/MC gel were evaluated in comparison with the control progesterone suspension. After the administration of PNS in F127/MC gel into the rats, a maximum serum concentration of 22.1 ± 1.9 ng/mL was reached at a T max of 4.05 ± 0.1 h. The terminal half life was 12.7 ± 0.8 h. The area under the curve AUC 0-∞ of the injected formula was 452.75 ± 42.8 ng·h/mL and the total mean residence time was 18.57 ± 1.44 h. The PNS in gel was significantly different from the control in rate and extent at P , 0.001. The natural progesterone which was nanosized and formulated in a thermosensitive gel significantly sustained the action of natural progesterone so that it could be injected every 36 h instead of every day. Moreover, this formula is expected to provide a much safer choice than the use of semi-synthetic progesterone.

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Plasma progesterone levels and cocaine-seeking in freely cycling female rats across the estrous cycle

Cited by 128 publications

References 56 publications

Aerobic exercise decreases the positive-reinforcing effects of cocaine

Aerobic exercise decreases the positive-reinforcing effects of cocaine

Altered levels of sex and stress steroid hormones assessed daily over a 28-day cycle in early abstinent cocaine-dependent females

Sustained-release progesterone nanosuspension following intramuscular injection in ovariectomized rats

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