Hunger and Satiation in the Structure of Temporal Organization of Impulse Activity of Masticatory Muscles in Rabbits

Abstract

Impulse activity of masticatory muscles, jaw elevators and depressors, during hunger, eating, and satiation was studied in chronic experiments on rabbits. The state of hunger is specifically reflected in the structure of temporal organization of impulse activity of proper masticatory muscles as a monomodal distribution of interpulse intervals and in activity of the mylohyoid muscle as bimodal distributions. Food intake induces reorganization of the temporal structure of impulse activity in both muscles manifesting in the form of similar bimodal patterns of distributions of interpulse intervals.

Reflection of induced and amplified food motivation in impulse activity of the masticatory muscles during electrostimulation of the “hunger center” in the lateral hypothalamus in rabbits

“…The generation of AP bursts in MM under conditions of LH electrostimulation in hungry and satiated animals in the absence of food anticipated by 118.07±1.51 msec the emergence of AP bursts in MMP, this indicating the reciprocal relationships between the masticatory center motoneurons innervating MM and MMP. We had previously found a similar regularity, then analyzing MM and MMP impulse activities during natural foodprocuring behavior [1,2].…”

“…The frequency of the MMP and MM AP burst-like rhythms during LH stimulation in the absence of food was lower than under conditions of food-procuring behavior forming on the basis of need in nutrients (Table 1, Table 2; p<0.05). The regulatory generation of AP bursts by the masticatory muscles during LH stimulation in the absence of food was an example of the anticipatory reaction, as it was not characteristic of food-procuring behavior formed on the basis of the need in nutrients [1,2]. The generation of AP bursts in MM under conditions of LH electrostimulation in hungry and satiated animals in the absence of food anticipated by 118.07±1.51 msec the emergence of AP bursts in MMP, this indicating the reciprocal relationships between the masticatory center motoneurons innervating MM and MMP.…”

“…Impulse activities of the m. masseter propria (MMP) and m. mylohyoideus (MM) were recorded via chronically implanted electrodes [1,2] during electric stimulation of the "hunger center" in the absence and presence of food in the experimental box in Chinchilla rabbits under conditions of free behavior after 24-food deprivation or fed before the experiment. In parallel, behavioral activity of animals was recorded using a webcamera.…”

“…The stimulation parameters were as follows: 20-30 Hz frequency, 0.2 msec pulse duration, and 2.5-3.5 V voltage. The temporal parameters of impulse activities of the masticatory muscles (in msec) were analyzed in an automated mode using AcqKnowledge software [1,2]. The temporal parameters of impulse activity of motor units (MU) of MMP and MM were processed using Statistica 6.0 software.…”