Alterations in the Solitary Tract Nucleus of the Rat Following Perinatal Food Restriction and Subsequent Nutritional Rehabilitation

Abstract

Newborn of altricial species maintain functional gustatory communication with the mother because the neural substrate and the capacity to discriminate and promote gustofacial responses are already operating. Because little is known about the effects of perinatal food restriction upon gustatory neuronal brain stem structures, we characterized neuronal Golgi-Cox alterations of the solitary tract rostral portion (NSTr) where gustatory information is known to convey in neonatal Wistar rats. Pre-and neonatally undernourished rats exhibited a general reduction in the number and extension of distal dendrites particularly in small neurons but little effect upon perikarya measurements of the NSTr neuronal population. By contrast, in nutritional and sensory rehabilitated rats the number of distal dendrites increased, although the dendritic extensions were less affected compared to perinatally underfed and control subjects. The data indicate that perinatal food restriction interferes with the NSTr dendritic arbor organization, while nutritional and sensorial rehabilitation given by normally lactating dams induced plastic changes presumably modifying the integrative processes underlying early taste discriminative capabilities. Moreover, since perinatal food restriction is a powerful stressor influence and the NST forms a part of a complex system underlying adaptive stress responses, the neuronal alterations observed here may be partly due to this noxious perinatal influence.

Organization of olfactory glomeruli in neonatally undernourished rats

“…The finding of significant reductions in body and brain weights concurrent with ear-and-eye-opening delays throughout the study is in line with previous reports showing that different perinatal underfeeding paradigms consistently interfere with food intake, physical growth, low emission of vocalizations and poor maternal care and delayed sensory maturation, particularly in the olfactory channel when the mother-litter bonds are at a critical stage and are essential for the pups' survival and brain growth (Salas et al 1970, Math and Davrainville 1980, Salas et al 1984, Almli et al 1985, Alberts and Cramer 1988, Diaz-Cintra et al 1994, Fleming et al 1999, Torrero et al 2000, Tonkiss et al 2003, Rubio et al 2004). …”

Development of the Gusto Facial Reflex in Perinatally Undernourished Rats

“…The GFR alterations in response to tastants found in the present study are in line with neuronal hypoplasia and the disorganization of the dendritic tree and spines observed along the relay nuclei of the gustatory and motor facial nucleus [7,13,15,36,37]. In this regard, it is known that descending input from the insular cortex, lateral hypothalamus, and central amygdale modulate the brainstem sensory and motor mechanisms of the newborn to produce fluid and food intake, nipple attachment, and the GFR integration that seems to be disrupted in the UG animals studied here [19,[38][39][40][41].…”

“…In the past, a number of studies have shown that perinatal undernutrition in the rat delays the maturation of sensory systems and causes the expression of altered motor patterns; these effects lead to a significant deficiency of somatosensory, auditory, visual, and chemosensory stimulation that may be essential for long-term behavioral performance [1][2][3][4][5][6][7][8]. Perinatal undernutrition mainly interferes with the anatomical organization of central nervous system (CNS) areas which undergo a phase of postnatal cell proliferation; these areas include the cerebral and cerebellar cortices, the hippocampus, central amygdaloid nucleus, olfactory bulb, and solitary tract nucleus, and they participate in the head movements, mouth opening and closing, chewing, food ingestion, and chemosensory CNS integration [8,[9][10][11][12][13].…”

“…Perinatal undernutrition mainly interferes with the anatomical organization of central nervous system (CNS) areas which undergo a phase of postnatal cell proliferation; these areas include the cerebral and cerebellar cortices, the hippocampus, central amygdaloid nucleus, olfactory bulb, and solitary tract nucleus, and they participate in the head movements, mouth opening and closing, chewing, food ingestion, and chemosensory CNS integration [8,[9][10][11][12][13]. Early undernutrition affects neuronal development by reducing the cell number and their dendritic branching, and by the formation of spines with small perikarya alterations that interfere with their connectivity and neuronal interactions [7,8,[14][15][16].…”

Perinatal undernourishment and handling: effects on olfactory discrimination in the newborn rat

“…After birth, CG rats were fed by interchanging a pair of normally lactating dams every 12 h between litters as previously described. 47 This experimental procedure allows adequate nursing of pups and the care given by the mother (body licking, retrieving, thermal and tactile stimulation when crouching, anogenital stimulation, etc.) when the dams were interchanged between litters.…”