Sub-second changes in accumbal dopamine during sexual behavior in male rats

Abstract

Transient (200--900 ms), high concentrations (200--500 nM) of dopamine, measured using fast-scan cyclic voltammetry, occurred in the nucleus accumbens core of male rats at the presentation of a receptive female. Additional dopamine signals were observed during subsequent approach behavior. Background-subtracted cyclic voltammograms of the naturally-evoked signals matched those of electrically-evoked dopamine measured at the same recording sites. Administration of nomifensine amplified natural and evoked dopamine release, and increased the frequency of detectable signals. While gradual changes in dopamine concentration during sexual behavior have been well established, these findings dramatically improve the time resolution. The observed dopamine transients, probably resulting from neuronal burst firing, represent the first direct correlation of dopamine with sexual behavior on a sub-second time scale.

Time window of autoreceptor‐mediated inhibition of limbic and striatal dopamine release

“…Furthermore, in salient behavioral situations midbrain dopamine neurones are reported to fire synchronously in bursts (Schultz, 1986). This doubtlessly causes dopamine release from many terminals simultaneously and results in very high, but transient, concentrations of extracellular dopamine (Rebec et al, 1997;Robinson et al, 2001). The window of autoreceptor action demonstrated here would permit the rapid rise in dopamine for the burst, while curbing dopamine levels during periods of tonic firing.…”

Prefrontal Cortex Stimulation Induces 2-Arachidonoyl-Glycerol-Mediated Suppression of Excitation in Dopamine Neurons

“…Importantly, burst firing of DA neurons leads to larger and transient extracellular DA concentrations as compared with single spiking (Gonon, 1988). Indeed, transient and phasic increases of DA levels in the target regions (subcortical and cortical) are associated with increased bursting probability as well as reward- ing and alerting stimuli (Rebec et al, 1997;Robinson et al, 2001;Wightman and Robinson, 2002). Furthermore, phasic released DA serves distinct physiological and behavioral functions depending on the target area: subcortical DA influences motivation, psychomotor activation, and reward craving, whereas cortical DA has an effect on working memory, stress, and reward anticipation (Jentsch et al, 2000;Wightman and Robinson, 2002).…”

“…Thus, the finding that VTA DA cells respond to PFC stimulation with an increased spiking and bursting probability, as well as an augmented frequency within the bursts, when the endocannabinoid retrograde signal is disrupted, strongly suggests that this retrograde signal might attribute incentive salience to otherwise irrelevant stimuli and also be involved in altered stress responses (such as those observed in CB1 knock-out mice) (Marsicano et al, 2002;Haller et al, 2004). Indeed, phasic and transient DA release occurs in response to a new environment (Rebec et al, 1997) and/or stimulus (Robinson et al, 2001), consistent with the idea that phasic DA serves as an alerting signal, and contributes to associative phases of reward (Wightman and Robinson, 2002). On the other hand, activation of CB1 receptors after Cannabis use transiently induces cognitive deficits (e.g., impaired attention, altered perception, lack of motivation, and deficits in working memory) (D'Souza et al, 2004) resembling those associated with endogenous psychotic disorders such as schizophrenia.…”

Detecting Subsecond Dopamine Release with Fast-Scan Cyclic Voltammetry in Vivo

“…In the striatum, these tonic concentrations of dopamine are predicted to be [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] nmol/L by microdialysis (9 ) and differential normalpulse voltammetry (10 ) and 50 -100 nmol/L by theoretical estimations using fast-scan cyclic voltammetry (11 ) and pharmacologic studies (12 ). If the concentrations are indeed 20 nmol/L or above, those dopamine receptors in high-affinity states would be chronically occupied, which appears to be the case for D 2 -like receptors (13,14 ).…”