Further studies on the rat posterodorsal medial amygdala: dendritic spine density and effect of 8-OH-DPAT microinjection on male sexual behavior.
The rat posterodorsal medial amygdala (MePD) is a component of the neural network that modulates male sexual behavior. Dendritic spines were counted in Golgi-impregnated bitufted and stellate neurons and from cells located in the medial and lateral MePD subregions. It was also studied the effect of 8-OH-DPAT, a 5-HT1A receptor agonist, microinjected into the MePD on male sexual behavior. There were no significant differences in the dendritic spine density obtained from multipolar bitufted and stellate neurons (n = 48 cells in each group; p > 0.05) or in the data from the medial or the lateral MePD (n = 48 neurons per region; p > 0.05). Rats were stereotaxically microinjected into the MePD with saline (0.2 microl, n = 6) or 8-OH-DPAT (0.1 and 1.0 microg/0.2 microl, n = 6 and 5, respectively). Behavioral recordings prior to surgery and "non-target" microinjections served as additional control data. 8-OH-DPAT 1.0 microg decreased the latencies to intromission and ejaculation, the postejaculatory refractory period and the mount frequency when compared to control pre-surgery data (p < 0.05). When compared among groups, 8-OH-DPAT 1.0 microg promoted the highest percentage reduction in the postejaculatory refractory period. Saline and injections in the vicinity of MePD did not promote relevant effects on ejaculation (p > 0.05). Results indicate that a similar dendritic spine density can be found in morphologically different populations of MePD neurons and, 8-OH-DPAT can facilitate male sexual behavior by acting on postsynaptic 5-HT1A receptors in this brain area.
Laboratório de Neurociências, Centro 2, Universidade do Vale do Rio dos Sinos, São Leopoldo RS 93022-000, Brazil.
Juliana
J
de Castilhos
Simone
S
Marcuzzo
Cláudia D
CD
Forti
Rosana M
RM
Frey
Dirson
D
Stein
Matilde
M
Achaval
Alberto A
AA
Rasia-Filho
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000679:Amygdala / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D048430:Cell Shape / Q000502:physiology; D049229:Dendritic Spines / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure*; D004305:Dose-Response Relationship, Drug; D004542:Ejaculation / Q000187:drug effects / Q000502:physiology; D005260:Female; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D044282:Receptor, Serotonin, 5-HT1A / Q000187:drug effects / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D017366:Serotonin Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin