Influence of Acute Exercise on Postprandial Lipemia and Fat Oxidation in Active Cannabis Users

Adults residing in industrialized nations spend most of their day in a postprandial state. This can cause prolonged elevated levels of triglycerides and glucose post-meal, leading to increased risk of cardiovascular and metabolic disease. In epidemiological literature, cannabis users have been reported to have similar or lower levels of blood lipids compared to nonusers. However, postprandial responses and whether prior exercise improves postprandial lipemia (PPL) in this population is not known. PURPOSE: To examine the influence of prior exercise on PPL in active cannabis users. METHODS: This analysis presents preliminary data from a larger ongoing study comparing prior exercise and PPL in cannabis users and non-users. Seven active cannabis users (Age: 30 ± 7 years; BMI: 24.3 ± 3.4 kg/m2; VO2max: 47.5 ± 10.8 mL/kg/min) completed 1 hour of exercise at their ventilatory threshold (VT) the evening before a high-fat, high-sugar liquid meal containing 15 kcal/kg body mass. Substrate oxidation, blood pressure, and capillary blood samples were obtained before and every 30-60 minutes post-meal for 3 hours. Blood samples were analyzed for glucose and triglycerides. Repeated-measures ANOVAs were utilized to examine differences in variables between conditions, across time, and their interaction. Area-under-the-curve (AUC) for glucose and triglycerides were calculated by the trapezoidal rule. RESULTS: Participants exercised at an intensity of 96 ± 5% VT (73 ± 11% VO2max) and expended 790 ± 168 kcals with an average RER of 0.92 ± 0.03. Post meal (1141 ± 200 kcals), all variables had significant effects of time (p \u3c 0.05), but no significant effect of condition (Control vs. Exercise) or interaction (p \u3e 0.05). AUC for triglycerides (p = 0.057) and glucose (p = 0.243) were not significantly different between conditions. CONCLUSION: In the present analysis, exercise did not acutely affect cardiovascular or metabolic responses to a high-fat, high-sugar liquid meal. Larger sample sizes will facilitate better comparisons

Aspects of the behavioral and endocrine ontogeny of six moustached tamarins, Saguinus mystax (Callitrichinae)

Deutsche Forschungsgemeinschaft (HE 1870/10-1,2

Prior acute exercise restores postprandial fat oxidation in active cannabis users

Abstract Data suggest cannabis users have similar or lower levels of blood lipids compared to nonusers. However, the extent to which cannabis users experience postprandial lipemia is not known. Eleven cannabis users and 11 nonusers completed either rest or 1 h of exercise at their ventilatory threshold the evening before a meal tolerance test (MTT). Substrate oxidation, blood pressure, and capillary blood were obtained before and every 30–60 min post‐meal for 3 h. Linear mixed models were utilized to examine differences in variables between groups, conditions, across time, and their interactions. Exercise led to increased fat oxidation post‐MTT (p  0.05). This study indicated that prior exercise improves lipid metabolism in cannabis users and nonusers after a high‐fat meal test. Cannabis users appear sensitive to the effects of exercise. Future studies should incorporate additional meals and variables related to cardiovascular health and metabolism

Retrieval-specific endocytosis of GluA2-AMPARs underlies adaptive reconsolidation of contextual fear

Upon retrieval, fear memories are rendered labile and prone to modification, necessitating a restabilization process of reconsolidation to persist further. This process is also crucial for modulating both strength and content of an existing memory and forms a promising therapeutic target for fear-related disorders. However, the molecular and cellular mechanism of adaptive reconsolidation still remains obscure. Here we show that retrieval of fear memory induces a biphasic temporal change in GluA2-containing AMPA-type glutamate receptor (AMPAR) membrane expression and synaptic strength in the mouse dorsal hippocampus. Blockade of retrieval-induced, regulated, GluA2-dependent endocytosis enhanced subsequent expression of fear. In addition, this blockade prevented the loss of fear response after reconsolidation-update of fear memory content in the long-term. Thus, endocytosis of GluA2-containing AMPARs allows plastic changes at the synaptic level that exerts an inhibitory constraint on memory strengthening and underlies the loss of fear response by reinterpretation of memory content during adaptive reconsolidation. © 2011 Nature America, Inc. All rights reserved