Progesterone Enhancement of Lysergic Acid Diethylamide and Levo-5-Hydroxytryptophan Stimulation of the Copulatory Response in the Female Rat
Anni Sietnieks, Bengt J. Meyerson
Neuroendocrinology March 26, 2008 DOI: 10.1159/000123499 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Ovariectomized rats |
| Interventions | Lysergic acid diethylamide (LSD) Levo-5-hydroxytryptophan (L-5-HTP) estradiol benzoate progesterone pargyline R04-4602 |
| Dose | LSD 10 μg/kg, LSD 1 μg/kg, L-5-HTP 0.25 and 0.05 mg/kg, estradiol benzoate 25 or 7 × 2 μg/kg or 5 μg/kg, progesterone 4.0 mg/rat |
| Topics | LSD |
| Citations | 11 |
| Key findings | Small doses of LSD and L-5-HTP stimulate lordosis behavior in ovariectomized rats, and this stimulatory effect is enhanced by progesterone treatment. |
Abstract
Copulatory behavior in the ovariectomized rat, i.e. the lordosis response (LR) on being mounted by a male, can be induced by administration of either estrogen alone or estrogen followed by progesterone. LR has been shown to be inhibited by lysergic acid diethylamide (LSD) in certain doses (≥50 μg/kg) and by Levo-5-hydroxytryptophan (L-5-HTP) (≥2.5 mg/kg). This effect was recently found to be enhanced by increasing doses of progesterone. In contrast, small doses of LSD (5–30 μg/kg) have been shown to increase LR activated by estrogen alone. The effects of various hormone treatments on the stimulatory action of LSD were tested in the present study. When the lordosis behavior was activated by estradiol benzoate (EB) alone (25 or 7 × 2 μg/kg), LR increased 10 min after injection of LSD in a dose of 10 μg/kg. There were no detectable effects in animals treated with estrogen alone when the dose of LSD was lowered to 1 μg/kg. LSD in the latter dose gave an increased response, however, when LR was activated by EB (5 μg/kg) in combination with progesterone (4.0 mg/rat). An analogous study was conducted with L-5-HTP, after pretreatment with pargyline and R04–4602. Small doses of L-5-HTP (0.25 and 0.05 mg/kg) stimulated the LR and the influence of progesterone was the same as for small doses of LSD. Possible mechanisms underlying the observed influence of progesterone on serotonergic mechanisms involved in the lordosis behavior are discussed.
Comparable studies
Other preclinical and animal studies on LSD, most cited first.