JOURNAL ARTICLE

Catecholaminergic neurons in synaptic connections with pre-Bötzinger complex neurons in the rostral ventrolateral medulla in normoxic and daily acute intermittent hypoxic rats

Jun-Jun Kang, Wei-Hua Liang, Chun-Sing Lam, Xiao-Feng Huang, Shou-Jing Yang, Margaret T T Wong-Riley, Man-Lung Fung, Ying-Ying Liu
Experimental Neurology 2017, 287 (Pt 2): 165-175
27240519
The rostral ventrolateral medulla (RVLM) contains cardiovascular-related catecholaminergic neurons and respiratory-related pre-Bötzinger complex (pre-BötC) neurons, which are intermingled and functionally connected for coordinating cardiorespiratory activities. Daily acute intermittent hypoxia (dAIH) is known to elicit respiratory plasticity. However, it is unclear if the catecholaminergic neurons directly synapse onto pre-BötC neurons, and if the local circuitry exhibits plasticity when exposed to dAIH. The present study was aimed to determine the synaptic phenotypes between dopamine-β-hydroxylase (DβH)-immunoreactive (ir) catecholaminergic neurons and neurokinin 1 receptor (NK1R)-ir pre-BötC neurons, and the effect of dAIH on the neuronal network. Immunofluorescence histochemistry was used to reveal immunoreactivities of DβH and NK1R in the RVLM of normoxic and dAIH rats. Synaptic phenotypes were examined with double-labeling immunoelectron microscopy. We found that DβH immunoreactivity was expressed in somata and processes, some of which were in close apposition to NK1R-ir pre-BötC neurons. DβH-ir gold particles were localized to somata, dendrites, and axonal terminals. DβH-ir terminals formed asymmetric synapses, and occasionally, symmetric synapses in the pre-BötC, featuring the local circuitry. Of the synapses, 28% in normoxic and 29.6% in dAIH groups were apposed to NK1R-ir dendrites. Significant increases in DβH expression and NK1R-ir processes were found in the dAIH group. Moreover, the area and number of processes in close appositions were significantly elevated, strongly suggesting that dAIH induced plasticity with increased connections and interactions between the cardiovascular- and respiratory-related neurons in the local circuitry. In conclusion, asymmetric synapses are predominant in the crosstalk between catecholaminergic and pre-BötC neurons in the RVLM, elaborating excitatory transmission driving the coupling of cardiorespiratory activities. The neural network manifests plasticity in response to dAIH challenge.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
27240519
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"