Short-term plasticity in excitatory synapses of the rat medial preoptic nucleus.
The medial preoptic nucleus (MPN) regulates sexual behavior which is subject to experience-dependent modifications. Such modifications must depend on functional plasticity in the controlling neural circuits. Thus, MPN synapses are likely candidates for the site of alterations. The present work is a first systematic study of functional synaptic plasticity at glutamatergic synapses in the MPN. Short-term activity-dependent plasticity was investigated using a slice preparation from young male rats. The average efficacy of AMPA/kainate-receptor-mediated synaptic transmission was activity-dependent, showing a peak at a steady stimulation rate of 2 Hz. The variation in efficacy was attributed to mainly presynaptic factors since the average response amplitude was roughly paralleled by the response probability. Upon paired-pulse stimulation, paired-pulse facilitation as well as paired-pulse depression was observed. In some cases, paired-pulse facilitation as well as paired-pulse depression was recorded from an individual neuron depending on the interval between the paired stimuli. On average, paired-pulse facilitation was observed at intervals <500 ms, and paired-pulse depression at intervals in the range 1-4 s. The findings thus reveal complex activity-dependent short-term plasticity of the functional synaptic properties in the medial preoptic nucleus.
Malinina
Evgenya
E
Department of Integrative Medical Biology, Section for Physiology, Umeå University, Umeå, Sweden.
Druzin
Michael
M
Johansson
Staffan
S
D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology* / Q000528:radiation effects; D066298:In Vitro Techniques; D009473:Neuronal Plasticity / Q000502:physiology*; D011301:Preoptic Area / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000502:physiology*; D013997:Time Factors