Effect of Direct and Mediated through Maternal Organism Activation of the Catecholaminergic System on Heart Rate Parameters in Rat Fetuses

We performed a comparative analysis of direct and mediated through the maternal organism effects of elevated catecholamine concentration on changes in the cardiac activity parameters in female rats and their fetuses on gestation days 18 and 20 under in vivo conditions. Administration of L-DOPA, a precursor of catecholaminergic transmitters, did not cause chronotropic effects in fetuses. Analysis of HR variability showed that in fetuses, irrespective of the administration route, there was an increase in nervous influences while the leading role of humoral-metabolic factors in the regulation of HR was preserved. In females receiving L-DOPA injection on day 18 of gestation, a decrease in humoral-metabolic and an increase in nerve effects were observed; in rats injected with L-DOPA on day 20 of gestation, an increase in sympathetic influences was found. Administration of L-DOPA to fetuses provoked a slight increase in the power of all components of the heart rhythm periodogram spectrum in females on day 18 of gestation and their decrease on day 20. Changes in the parameters of HR variability in females can confirm the hypothesis that in the "mother-fetus" system, the heart rhythm in the mother can be affected by both maternal and fetal influences presumably through the humoral-metabolic regulation.

Mother-Young Bonding: Neurobiological Aspects and Maternal Biochemical Signaling in Altricial Domesticated Mammals

Mother-young bonding is a type of early learning where the female and their newborn recognize each other through a series of neurobiological mechanisms and neurotransmitters that establish a behavioral preference for filial individuals. This process is essential to promote their welfare by providing maternal care, particularly in altricial species, animals that require extended parental care due to their limited neurodevelopment at birth. Olfactory, auditory, tactile, and visual stimuli trigger the neural integration of multimodal sensory and conditioned affective associations in mammals. This review aims to discuss the neurobiological aspects of bonding processes in altricial mammals, with a focus on the brain structures and neurotransmitters involved and how these influence the signaling during the first days of the life of newborns.

Changes in Activities of Somatovisceral Systems in Newborn Rats under Conditions of Nicotinic Cholinoreceptor Blockage and Activation of Cholinoreactive Structures

Relationship between the residual effects of disorders in the cholinergic system and the activities of the cardiac, respiratory, and somatomotor systems of 1- and 16-day-old rats were studied. Experiments were carried out on intact conscious rats before and after drug injection (nicotinic cholinoreceptor blocker benzohexonium). In order to increase the level of cholinoreactive structure activation, acetylcholinesterase inhibition by eserine was carried out. Injection of benzohexonium caused rarefaction of HR, respiration rate, and a decrease of motor activity parameters in rats of both age groups. Injection of eserine after cholinolytic premedication led to further rarefaction of the respiration rate and HR. The reaction of the somatosensory system to changed level of cholinoreactive structure activation was age-specific. Motor activity increased in 1-day-old rats and was depressed significantly in 16-day-old ones.