Neurons expressing serotonin-1B receptor in the basolateral nuclear group of the amygdala in normally behaving and aggressive dogs

The brain of the tree pangolin (Manis tricuspis). VII. The amygdaloid body

Here, we describe the cytoarchitecture and chemoarchitecture of the amygdaloid body of the tree pangolin. Our definition of the amygdaloid body includes the pallial portions of the amygdala, and the centromedial group that is a derivative of the subpallium and part of the extended amygdala. The remainder of the extended amygdala is not described herein. Within the amygdaloid body of the tree pangolin, we identified the basolateral group (composed of the lateral, basal, and accessory basal amygdaloid nuclei), the superficial, or cortical nuclei (the anterior and posterior cortical nuclei, the periamygdaloid cortex, and nuclei of the olfactory tract), the centromedial group (the central amygdaloid nucleus and the medial nuclear cluster), and other amygdaloid nuclei (the anterior amygdaloid area, the amygdalohippocampal area, the intramedullary group, and intercalated islands). The location within and relative to each other within the amygdaloid body and the internal subdivisions of these groups were very similar to that reported in other mammalian species, with no clearly derived features specific to the tree pangolin. The only variation was the lack of an insular appearance of the intercalated islands, which in the tree pangolin were observed as a continuous band of neurons located dorsomedial to the basolateral group similar in appearance to and almost continuous with the intramedullary group. In carnivores, the closest relatives of the pangolins, and laboratory rats, a similar appearance of portions of the intercalated islands has been noted.

Genetics of canine behavior: A review

The past decade has seen rapid progress in the field of canid behavioral genetics. The recent advances are summarized in this review. The identification of the genes responsible for tameness in silver foxes is the culmination of a half century of behavioral testing and, more recently, genomic investigation. There is agreement that domestic dogs evolved from wolves, but when and from which population remains controversial. The genetic differences between wolves and dogs identified include those for neurotransmitters and digestion. Breed differences in behavior are well known, but only recently have the genetics underlying these differences been investigated. The genes responsible for flank sucking in Doberman Pinschers and for several other obsessive compulsive problems in other breeds have been identified. Aggression is the least desirable canine trait, and several laboratories have detected differences in neurotransmitters and their receptors between aggressive and non-aggressive dogs. In English Cocker Spaniels, the genes linked to aggressive behavior code for dopamine, serotonin, and glutamate receptors. A dopamine transporter gene has been associated with impulsive behavior in Malinois.

Cerebrospinal fluid substance P-like immunoreactivity correlates with aggression in personality disordered subjects

BACKGROUND

Neurochemical studies have pointed to a modulatory role in human aggression for a variety of central neurotransmitters; some seem to play an inhibitory role, whereas others seem to play a facilitory role in the modulation of aggression. Laboratory animal studies of substance P suggest a facilitory role for this undecapeptide in the modulation of aggression, but no studies of substance P have yet been reported with regard to human aggression.

METHODS

Basal lumbar cerebrospinal fluid samples were obtained from 38 physically healthy subjects with personality disorder (PD) and substance P-like immunoreactivity was measured and correlated with measures of aggression and impulsivity.

RESULTS

The cerebrospinal fluid substance P-like immunoreactivity levels were directly correlated with a composite measure of aggression and, more specifically, with Buss-Durkee Aggression. No correlation was seen with any measure of impulsivity or of general dimensions of personality.

CONCLUSIONS

These data suggest a direct relationship between central nervous system substance P containing neural circuits and aggression in human subjects. This finding adds to the complex picture of the central neuromodulatory role of impulsive aggression in human subjects.

The involvement of substance P in the induction of aggressive behavior

Aggression is a complex social behavior that involves a similarly complex neurochemical background. The involvement of substance P (SP) and its potent tachykinin receptor (NK1) in the induction of both defensive rage and predatory attack appears to be a consistent finding. However, an overall understanding of the nature of the SP involvement in the induction of aggressive behavior has not yet been fully achieved. The aim of this review is to summarize and present the current knowledge with regards to the role of SP in the induction of aggressive behavior and to synopsize: (a) its biochemical profile, and (b) the exact anatomical circuits through which it mediates all types of aggressive behavior. Future studies should seriously consider the potential use of this knowledge in their quest for the treatment of mood and anxiety disorders.