GABA and opioid binding distribution in the brain of the seizure-resistantProechimys guyannensis: An autoradiography study

Abstract

Proechimys guyannensis rodents present resistance to epilepsy. Autoradiography was used to map GABA(A) ((3)H-Muscimol), benzodiazepine ((3)H-Flunitrazepam), mu ((3)H-DAMGO), and delta ((3)H-DPDPE) opioid receptor binding in adult Proechimys guyannensis brain under normal conditions. Results were compared with values obtained from adult Wistar rats. Proechimys presented reduced (3)H-Muscimol binding in several cortices, thalamus, medial amygdala nucleus, and dorsal dentate gyrus. (3)H-Flunitrazepam binding was reduced in periaqueductal gray, frontal and entorhinal cortices, and enhanced in piriform cortex and ventral CA2 field of Ammons horn. Concerning (3)H-DAMGO binding, high values were found in several cortices, medial amygdala nucleus, dorsal dentate gyrus, and periaqueductal gray, whereas reduced binding was detected in anterior olfactory tubercle, cingulated cortex, thalamus, basolateral amygdala, substantia nigra, and dorsal and ventral CA fields. High (3)H-DPDPE binding was noticed in CA1 field from dorsal hippocampus, while reduced values were found in cingulate cortex, olfactory tubercle, thalamus, and substantia nigra. These findings provide the first description of receptor binding distribution of the Proechimys brain and suggest natural endogenous anticonvulsant mechanisms of theses rodents under normal conditions.

Robust Network Inhibition and Decay of Early-Phase LTP in the Hippocampal CA1 Subfield of the Amazon Rodent Proechimys

“…A plausible hypothesis to explain our data would be given by differences in GABA A quantification and distribution. Rocha et al ( 2006 ) performed quantitative receptor autoradiography to assess the distribution of high-affinity GABA A receptors through the powerful GABA A agonist [3H] muscimol and reported no differences between Proechimys and Wistar rats in GABA A binding quantification in the hippocampal subfields. On the other hand, it has been reported that the effect of inhibition on LTP seems to be stimulation-dependent (Chapman et al, 1998 ), thus the pattern of stimulation used in this study may play a role in the inhibition of population EPSP in the presence of bicuculline/picrotoxin.…”

Endogenous opiates and behavior: 2009

“…MOR possessed little overlap with preprotachykinin B in the dorsal horn of the spinal cord (917). The seizure-resistant rodents, Proechimys guyannesis, display high DAMGO binding in the medial amygdala, dorsal dentate gyrus and PAG, and decreased DAMGO binding in the anterior olfactory tubercule, cingulate cortex, thalamus, basolateral amygdala, SN and dorsal hippocampus (963). Whereas lower medial septal, but not MPOA MOR densities were lower in older reproductively senescent male Japanese quail than females or young males, DOR densities in both the medial septum and MPOA were lower in this group (871).…”

Duration of spermatogenesis and daily sperm production in the rodentProechimys guyannensis

“…A remarkable characteristic of this species is the high degree of development of the newborns (Arida et al , 2005; Scorza et al , 2011). Due to its resistance to chronic epilepsy, this species has been used as a model for this disease (Cavalheiro, 1995; Fabene et al , 2001; Arida et al , 2005; Rocha et al , 2006; Silva et al , 2014), being also, as a natural host, used in studies involving infectious parasites (Everard & Tikasingh, 1973). Investigations related to ecology and evolution of P. guyannensis are also available in the literature (Steiner et al , 2000; Eler et al , 2012; Silva et al , 2012).…”