Precontact 50-kHz vocalizations in male rats during acquisition of sexual experience.

Abstract

50-kHz ultrasonic vocalizations emitted by male rats during a 5-min period before introduction of a female (precontact vocalizations [PVs]) were analyzed in the context of acquisition of sexual experience. Changes in the main copulatory parameters and their N-methyl-D-aspartate (NMDA) receptor dependence, the role of contact with either anestrous or estrous females, and conditioning to odor and background cues were also investigated. Mount latency (ML) and intromission latency (IL) decreased after the 1st copulatory session, but ejaculation latency (EL) changed significantly only starting from the 4th session onward. The number of PVs gradually increased during the first 3-4 sessions. Blocking of NMDA receptors affected PVs and EL but not ML or IL. After a 5-month break in copulatory sessions, ML remained unchanged, whereas EL increased and the number of PVs decreased significantly. PVs were most robustly elevated by contact with estrous females. Exposure to background cues resulted in a linear decrease in number of PVs during 10 subsequent sessions without exposure to a female. The results suggest that, in the course of acquisition of a sexual experience, PVs reflect a learning process that depends on a rewarding value of sociosexual contact.

Limb use and complex ultrasonic vocalization in a rat model of Parkinson's disease: Deficit-targeted training

“…Subjects were male Long-Evans rats, aged 6 months, housed in groups of two in standard polycarbonate cages with sawdust bedding on a reversed 12:12 h light: dark cycle with food and water available ad libitum. Prior to 6-OHDA infusion all animals were sexually experienced to ensure calling to female rats [33]. A novel apparatus was used to isolate and record only the male acoustic output.…”

Social Transmission of Avoidance Behavior Under Situational Change in Learned and Unlearned Rats

“…Conversely, high-frequency vocalizations, often termed 50-kHz calls, occur during or in anticipation of juvenile rough-and-tumble play [19,20], mating [21][22][23][24][25][26][27][28], food consumption [29], electrical self-stimulation of the brain [29,30], and addictive drugs [31][32][33][34][35]. Furthermore, rats also emit such calls when tickled by a skilled experimenter in a playful way [36][37][38][39][40], and rates of 50-kHz calls were found to be positively correlated with the rewarding value of tickle stimulation as measured by instrumental approach behavior [36,37,39].…”

An NMDA antagonist impairs copulation and the experience-induced enhancement of male sexual behavior in the rat.

“…Thus, the NMDA antagonist apparently resulted in an acute impairment of copulation. Bialy et al (2000) did not observe an acute impairment by CGP 40116 on the first copulatory experience of their male rats. However, female rats treated with 0.1 mg/kg MK-801 Figure 4.…”

“…Experienced male rats show an increased preference for receptive females rather than males (Matuszczyk & Larsson, 1994) and require fewer mounts and intromissions to elicit ejaculation and less time to mount, intromit, and ejaculate (Bialy, Rydz, & Kaczmarek, 2000;Dewsbury, 1969;Larsson, 1978); they also take less time to resume copulation after ejaculating (Larsson, 1959). Copulation to one ejaculation also elicits more neural activation (measured as fos immunoreactivity) in the medial preoptic area of experienced males compared with naive males .…”

“…Fleming and Kucera (1991) reported that systemic administration of the NMDA antagonist dizocilpine maleate (MK-801) to male rats prior to initial sexual experience blocked the experience-induced enhancement of sexual behavior on drug-free tests 3, 6, or 9 days later. A different NMDA antagonist, CGP40116, blocked both the sexual experience-induced increase in precopulatory 50-kHz vocalizations and the decrease in ejaculation latency (Bialy et al, 2000).…”