Neuronal nitric oxide synthase immunopositive neurons in cat vestibular complex: a light and electron microscopic study

Abstract

Nitric oxide is a unique neurotransmitter, which participates in many physiological and pathological processes in the organism. Nevertheless, there are little data about the neuronal nitric oxide synthase immunoreactivity (nNOS-ir) in the vestibular complex of a cat. In this respect, the aims of this study were to: (1) demonstrate nNOS-ir in the neurons and fibers, from all major and accessory vestibular nuclei; (2) describe their light microscopic morphology and distribution; (3) investigate and analyze the ultrastructure of the NOS I-immunopositive neurons, fibers, and synaptic boutons. For demonstration of the nNOS-ir, the peroxidase-antiperoxidase-diaminobenzidin method was applied. Immunopositive for nNOS neurons and fibers were present in all major and accessory vestibular nuclei. On the light microscope level, the immunopositive neurons were different in shape and size. According to the latter, they were divided into four groups--small (with diameter less than 15 microm), medium-sized (with diameter from 15 to 30 microm), large type I (with diameter from 30 to 40 microm), and large type II (with diameter greater than 40 microm). On the electron microscope level, the immunoproduct was observed in neurons, dendrites, and terminal boutons. According to the ultrastructural features, the neurons were divided into three groups--small (with diameter less than 15 microm), medium-sized (with diameter from 15 to 30 microm), and large (with diameter greater than 30 microm). At least two types of nNOS-ir synaptic boutons were easily distinguished. As a conclusion, we hope that this study will contribute to a better understanding of the functioning of the vestibular complex in cat and that some of the data presented could be extrapolated to other mammals, including human.

Neuronal nitric oxide synthase immunopositive neurons in cat claustrum—a light and electron microscopic study

“…86-23, revised 1996). Our perfusion protocol was described in details elsewhere (Papantchev et al 2006). In brief-all animals were deeply anesthetized with intraperitoneal injection of Urethan (40 mg/kg) and transcardialy perfused with 500 ml heparinized saline followed by 3,000 ml phosphate buffered saline (PBS; pH 7.4) containing 2.5% glutaraldehyde and 4% parafomaldehyde.…”

“…Our protocol for immunohistochemical visualization of nNOS was already described elsewhere (Papantchev et al 2006). In brief-all slices, prepared as described above, were treated with sodium borohydride for 45 min followed by three consecutive rinses in 0.01 M PBS, each for 2 min.…”

“…It was shown that it takes part in many processes in the central nervous system like synaptic plasticity in the hippocampus (Krushkov et al 1996), claustral functioning (Hinova-Palova et al 1997), eye movements (Moreno-Lopez et al 1996, thalamic functioning (Krushkov et al 1996), blood pressure control (Maeda et al 1999), inferior colliculus functioning , vestibular complex functioning (Papantchev et al, , 2006 and so forth. NO is synthesized by the enzyme Nitric oxide synthase (NOS).…”

“…During the last years a lot of studies on NOS and NO have been performed (Mizukawa et al 1989, Mizukawa 1990, Dawson et al 1991a, 1991b, 1994, Hope et al 1991, Rodrigo et al 1994, Kullo et al 1997, Soares et al 2003, Marino and Cudeiro 2003, Papantchev et al 2003, 2006, Sears et al 2004, Seyidova et al 2004. Nevertheless there are little data about the neuronal Nitric oxide synthase immunoreactive (nNOS-ir) neurons and fibers in the dorsal claustrum (DC) of a cat.…”

Expression and colocalization of NADPH-diaphorase and heme oxygenase-2 in trigeminal ganglion and mesencephalic trigeminal nucleus of the rat

“…Nitric oxide (NO) is a short-lived free radical involved in various functions (Holmqvist et al 2006;Rodini et al 2008), which action in the nervous system has been extensively studied (Papantchev et al 2006;McDonald et al 2007). NO is biosynthesized from L-arginine via a family of nitric oxide synthase (NOS).…”