Effects of intracerebroventricular bombesin administration on local cerebral glucose utilization in the restrained and unrestrained rat

Intracerebroventricular (ICV) administration of bombesin (BN) induces a syndrome characterized by stereotypic locomotion and grooming, hyperactivity and sleep elimination, hyperglycemia and hypothermia, hyperhemodynamics, feeding inhibition, and gastrointestinal function changes. Mammalian BN-like peptides (MBNs), e.g. gastrin-releasing peptide (GRP), Neuromedin C (NMC), and Neuromedin B (NMB), have been detected in the central nervous system. Radio-labeled BN binds to specific sites in discrete cerebral regions. Two specific BN receptor subtypes (GRP receptor and NMB receptor) have been identified in numerous brain regions. The quantitative 2-[14C]deoxyglucose ([14C]20G) autoradiographic method was used to map local cerebral glucose utilization (LCGU) in the rat brain following ICV injection of BN (vehicle, BN O.1Jlg, O.5Jlg). At each dose, experiments were conducted in freely moving or restrained conditions to determine whether alterations in cerebral function were the result of BN central administration, or were the result of BN-induced motor stereotypy. The anteroventral thalamic nucleus (AV) (p=O.029), especially its ventrolateral portion (AVVL) (plocalized alteration in cerebral metabolism within parts of the anterior thalamus, which is the principle relay in the limbic circuitry. BN effects were also observed in IGr, Mi, SCh, and ME. Effects of restraint were found in LOVL, LOOM, and LG. It is suggested that increased LCGU in AV and AVVL may be the result of functional change in the limbic circuitry and the hypothalamus caused by BN receptor functional modification. In IGr, increased LCGU following BN administration is considered to be mainly the result the activation of NMB receptor, a subtype of BN receptors. In SCh, increased LCGU is believed to be caused both by BN effects on the thalamic, the hypothalamic, and the limbic functions and by activation of GRP receptor, another BN receptors subtype found in SCh. In ME, increased LCGU is suggested to be caused by BN effects on the hypothalamic functions, especially those related to the neuroendocrine functions. None of the alterations seen in these regions reflects the emission of stereotyped motor behaviors. Rather, they reflect a direct influence of BN central administration upon functioning of the cerebral regions influenced by BN administration. The restraint effects seen in LO, including LOOM and LOVL, are suggested to be the result of altered behavioral expression. The restraint effects seen in LG is suggested to be the result of reduced locomotion.

The influence of familial smoking behaviours on adolescent smoking behaviours

The ability to identify adolescents who are at risk for becoming smokers may prove useful in developing effective smoking prevention programs. The purpose of this stUdy was to assess the importance of familial smoking behaviours on adolescent smoking patterns. The results were based on responses to The Grade 7 Lincoln County Smoking Survey designed by Chudzik and Partington (1994), and are a part of the "Peer Assisted Learning Program· (PAL) presented by the Niagara Regional Health Services Department, with the cooperation of a local Board of Education (Region of Niagara). The results indicate that 12% of the total group of 450 Grade 7 student respondents were current smokers at the time the data were collected (13% males and 11% females), while more than 37% of individuals indicated that they had tried smoking previously. Of the individuals who were classified as smokers, 11% reported that they smoked because their parents smoked, but only 6% reported that they smoked because their siblings smoked. More concerning, however, is the finding that 4% of smokers reported that they felt pressured to smoke by their relatives. In a society that is becoming increasingly concerned about health, it is also alarming to observe that only 50% of the respondents within this sample reported that there were no smokers (parents/siblings) in their homes. The results also indicate that 33% percent of respondents had grandparents who continued to smoke, and 53% of respondents indentified other relatives who continued to smoke.