Neonatal adjustments in respiratory and pulse rates in tropical breeds of buck-kids and doelings

Background The transition to pulmonary respiration and the termination of foetal cardiovascular shunts is expected to commence immediately after birth. Subsequently, alveolar ventilation and tissue perfusion must be established, despite the challenge of extra-uterine environmental conditions, which could be quite demanding, even to the adult animals. The current study evaluated neonatal adjustment and diurnally induced changes in respiratory and pulse rates in kids of Red Sokoto, Sahel and West African Dwarf (WAD) goats in a tropical climate. Results Morning and afternoon respiratory rates started decreasing (P < 0.05) in the second week of birth. The pulse rate in the morning hours rose (P < 0.05) on Day 1 with no significant fluctuation subsequently, while the pattern in the afternoon hours showed a progressive decrease (P < 0.05) after birth. Apart from the day of birth, respiratory rate on other days increased significantly from morning to afternoon hours. The afternoon pulse rate was higher (P < 0.05) on the day of birth, but lower (P < 0.05) on Day 2 as compared to the morning values; and no diurnal difference was observed in subsequent days. The WAD goats had significantly higher respiratory and pulse rates than Red Sokoto and Sahel kids, especially in the afternoon hours. Similarly, the values were higher (P < 0.05) in doelings than buck-kids during the morning hours. The correlation between respiratory and pulse rates was positive (P < 0.05) and the strength of the association increased with age. Conclusion It was concluded that the afternoon rise in ambient temperature induced the establishment of a clear diurnal variation in respiratory rate 24 h postnatal, while the diurnal variation in pulse rate was weak and irregular. The tropical climate may be quite challenging to the attainment of physiological stability in respiratory and cardiovascular functions of neonatal goat kids, especially during the hot season.

1. What is an amphibian?

‘What is an amphibian?’ provides an overview of amphibians, which zoologists divide into three very unequal sized Orders. The great majority are the frogs and toads, which make up the order Anura, a name that refers to the lack of a tail. The second amphibian order are the salamanders and newts, called the Urodela. Meanwhile, the third amphibian order, the Caecilia, are best known for being poorly known, thanks to their remote distribution and obscure habitat. There are four methods that amphibians can use to breathe: cutaneous respiration, bucco-pharyngeal respiration, pulmonary respiration, and branchial respiration.

BMP9 and BMP10 are necessary for proper closure of the ductus arteriosus

The transition to pulmonary respiration after birth requires rapid alterations in the structure of the mammalian cardiovascular system. One dramatic change that occurs is the closure of the ductus arteriosus (DA), an arterial connection in the fetus that directs blood flow away from the pulmonary circulation. Two members of the TGFβ family, bone morphogenetic protein 9 (BMP9) and BMP10, have been recently involved in postnatal angiogenesis, both being necessary for remodeling of newly formed microvascular beds. The aim of the present work was to study whether BMP9 and BMP10 could be involved in closure of the DA. We found that Bmp9 knockout in mice led to an imperfect closure of the DA. Further, addition of a neutralizing anti-BMP10 antibody at postnatal day 1 (P1) and P3 in these pups exacerbated the remodeling defect and led to a reopening of the DA at P4. Transmission electron microscopy images and immunofluorescence stainings suggested that this effect could be due to a defect in intimal cell differentiation from endothelial to mesenchymal cells, associated with a lack of extracellular matrix deposition within the center of the DA. This result was supported by the identification of the regulation by BMP9 and BMP10 of several genes known to be involved in this process. The involvement of these BMPs was further supported by human genomic data because we could define a critical region in chromosome 2 encoding eight genes including BMP10 that correlated with the presence of a patent DA. Together, these data establish roles for BMP9 and BMP10 in DA closure.

Behavioural and network plasticity following conditioning of the aerial respiratory response of a pulmonate mollusc

Most molluscs perform respiration using gills, but the pulmonate molluscs have developed a primitive lung with which they perform pulmonary respiration. The flow of air into this lung occurs through an opening called the pneumostome, and pulmonate molluscs travel to the surface of the water to obtain oxygen from the surrounding atmosphere. The aerial respiratory behaviour of the pulmonate mollusc, the great pond snail (Lymnaea stagnalis (L., 1758)), has been well studied, and a three-neuron central pattern generator (CPG) controlling this rhythmic behaviour has been identified. The aerial respiratory behaviour of L. stagnalis can be operantly conditioned and plasticity within the CPG has been associated with the conditioned response. In this review, we describe both the aerial respiratory behaviour and the underlying neuronal network of this pulmonate mollusc, and then discuss both the behavioural and network plasticity that results from the conditioning of this behaviour.