The effect of 90 days of hypokinetic stress on the ultrastructure of axo-dendritic synapses and porosomes in the rat central nucleus of the amygdala was investigated. In some presynaptic terminals significant pathological alterations, such as agglutination of synaptic vesicles, occurrence of vacuoles, osmiophilic and membrane-like bodies or the destruction of presynaptic mitochondria, were revealed. Furthermore, an increase in the number of synaptic preterminals with granular and/or single synaptic vesicles or modifications in the osmiophilicity of synaptic contacts and/or types of spines were observed. In such synapses pathological or some other modifications in synaptic plasticity or in the transmission process may take place. There were no alterations in the main structural parameters (diameter and depth) of the porosome.