Distribution of somatostatin-28 (1-12) immunoreactivity in the diencephalon and the brainstem of the dog

Abstract

The term somatostatin refers to a family of peptides, mainly somatostatin-14, somatostatin-28 and somatostatin-28 (1-12), which are the cleavage products of a single 116 amino acid-long preprosomatostain molecule. The production of antibodies to these peptides allows their localization in a number of neuronal populations throughout the entire neuroaxis in many mammals. The dog has been pointed out as an extremely useful animal model for studying age-related cognitive dysfunction and other neuronal changes associated with aging in which somatostatin appears to be involved. However, only very scanty information is available with regard to the distribution of somatostatin in the brain of the dog. In the present work we have determined the pattern of the distribution of somatostatin-28 (1-12) immunoreactivity in the diencephalon and the brainstem of the dog. High to moderate densities of labeled perikarya were found in the anterior periventricular and arcuate hypothalamic nuclei, the reticular thalamic nucleus, in delimited parts of the nucleus of the brachium inferior colliculus, the retrorubral area, the dorsal raphe nucleus, the myelencephalic reticular formation and the dorsal motor nucleus of the vagus. Less dense population of somatostatin cells were localized in other diencephalic and brainstem nuclei. The distribution of labeled fibers was even broader as in addition to those above mentioned there were a number of areas that appeared devoid of labeled perikarya. Many of the findings were similar to those reported in earlier works while others underlined the existence of inconsistencies in the distribution pattern of this peptide in the brain of mammals.

Broad characterization of endogenous peptides in the tree shrew visual system

“…In contrast, we found that SOM 28 AA1-12 was present at high abundance in the superior colliculus. This is also consistent with previous findings based on autoradiography measurements in mouse [49], dog [50] and sheep [51] colliculus. This shows that different members of the Somatostatin family are expressed preferentially in different parts of the visual system.…”

Mapping of somatostatin‐28 (1‐12) in the alpaca (Lama pacos) brainstem

“…Also, sections were incubated omitting the primary antibody used in this study and no labelling was detected in any case. In addition, as previously reported (Coveñas et al, ; de León et al, ; Martín et al, ; Pego‐Reigosa et al, ), the preabsorption of the primary antibody with an excess of synthetic somatostatin‐28, somatostatin‐14, neuropeptide Y, angiotensin II, substance P, cholecystokinin, and methionine‐enkephalin was also carried out. Staining was not blocked in any of the cases.…”

“…The polyclonal primary antibody was raised in rabbits against immunogens prepared by coupling the synthetic peptide [somatostatin‐28 (1‐12)] to human serum albumin with glutaraldehyde, as previously reported (Coveñas et al, ; de León et al, ; Martín et al, ; Pego‐Reigosa et al, ). Rabbits were initially immunized with immunogens emulsified with Freund's complete adjuvant and at 2‐week intervals they were given booster doses of Freund's incomplete adjuvant.…”

“…It is known that these molecules are involved in a broad range of physiological actions (e.g., sleep, breathing, grooming, tactile stimulus, noradrenaline and growth hormone release inhibition, acetylcholine and serotonin release stimulation, and important effects on the motor cortex, hippocampus and the limbic system) (see Coveñas et al, ; see de León et al, ). It is also known that pro‐somatostatin‐derived peptides are widely distributed in the mammalian central nervous system (rat, guinea‐pig, cat, dog, monkey, humans) (see Coveñas et al, ; de León et al, ; Martín et al, ; Pego‐Reigosa et al, ).…”

Distribution of ACTH immunoreactivity in the diencephalon and the brainstem of the dog

“…However, there is a dearth of neuroanatomical data on the organization of the neurotransmitter systems in this species and on the response of these systems to aging (Kojima et al, 1983;Tafti et al, 1997). In this line of research, we have studied the anatomical organization of several neurotransmitter and neuropeptide systems in the brain of the dog Tomé et al, 1997;Pego-Reigosa et al, 2000;Pego-Reigosa et al, 2001;Pesini et al, 2001). The aim of the present work is to examine the distribution of ACTH in the brainstem of the dog and to compare it with the anatomical organization of the monoaminergic systems in this species and with previous reports on the distribution of ACTH in other mammals.…”